Patent Application
20140160452
The present invention relates to a lithographic apparatus, a programmable patterning device, and a device manufacturing method.
A lithographic apparatus is a machine that applies a desired pattern onto a substrate or part of a substrate. A lithographic apparatus may be used, for example, in the manufacture of integrated circuits (ICs), flat panel displays and other devices or structures having fine features. In a conventional lithographic apparatus, a patterning device, which may be referred to as a mask or a reticle, may be used to generate a circuit pattern corresponding to an individual layer of the IC, flat panel display, or other device). This pattern may be transferred on (part of) the substrate (e.g. silicon wafer or a glass plate), e.g. via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.
Instead of a circuit pattern, the patterning device may be used to generate other patterns, for example a color filter pattern, or a matrix of dots. Instead of a conventional mask, the patterning device may comprise a patterning array that comprises an array of individually controllable elements that generate the circuit or other applicable pattern. An advantage of such a “maskless” system compared to a conventional mask-based system is that the pattern can be provided and/or changed more quickly and for less cost.
Thus, a maskless system includes a programmable patterning device (e.g., a spatial light modulator, a contrast device, etc.). The programmable patterning device is programmed (e.g., electronically or optically) to form the desired patterned beam using the array of individually controllable elements. Types of programmable patterning devices include micro-mirror arrays, liquid crystal display (LCD) arrays, grating light valve arrays, and the like.
It is desirable, for example, to provide a flexible, low-cost lithography apparatus that includes a programmable patterning device.
In an embodiment, a lithographic apparatus is disclosed that includes a modulator configured to expose an exposure area of the substrate to a plurality of beams modulated according to a desired pattern and a projection system configured to project the modulated beams onto the substrate. The modulator may move the beams with respect to the exposure area. The lithographic apparatus may have an array of lenses to receive the plurality of beams, the array of lenses moveable with respect to the exposure area.
In an embodiment, the lithographic apparatus may, for example be provided with an optical column capable of creating a pattern onto a target portion of a substrate. The optical column may be provided with: a self emissive contrast device configured to emit a plurality of beams; and a projection system configured to project at least a portion of the plurality of beams onto the target portion. The apparatus may be provided with a deflector to move the beam with respect to the target portion.
The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate an embodiment of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.
FIGS. 33(A)-(C) is a schematic diagram of providing a donor material on a donor structure according to
FIGS. 34(A)-(I) is a schematic diagram of a donor structure and a method of manufacturing the donor structure according to an embodiment of the present invention.
FIGS. 35(A)-(C) is a schematic side view of a substrate patterning method according to an embodiment of the invention.
FIGS. 40(A)-(D) depict schematic top views and a side view of a part of a lithographic apparatus according to an embodiment of the present invention.
One or more embodiments of the present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers may indicate identical or functionally similar elements.
One or more embodiments of a maskless lithographic apparatus, a maskless lithographic method, a programmable patterning device and other apparatus, articles of manufacture and methods are described herein. In an embodiment, a low cost and/or flexible maskless lithographic apparatus is provided. As it is maskless, no conventional mask is needed to expose, for example, ICs or flat panel displays. Similarly, one or more rings are not needed for packaging applications; the programmable patterning device can provide digital edge-processing “rings” for packaging applications to avoid edge projection. Maskless (digital patterning) can enable use with flexible substrates.
In an embodiment, the lithographic apparatus is capable of super-non-critical applications. In an embodiment, the lithographic apparatus is capable of ≧0.1 μm resolution, e.g. ≧0.5 μm resolution or ≧1 μm resolution. In an embodiment, the lithographic apparatus is capable of ≦20 μm resolution, e.g. ≦10 μm resolution, or ≦5 μm resolution. In an embodiment, the lithographic apparatus is capable of ˜0.1-10 μm resolution. In an embodiment, the lithographic apparatus is capable of ≧50 nm overlay, e.g. ≧100 nm overlay, ≧200 nm overlay, or ≧300 nm overlay. In an embodiment, the lithographic apparatus is capable of ≦500 nm overlay, e.g. ≦400 nm overlay, ≦300 nm overlay, ors 200 nm overlay. These overlay and resolution values may be regardless of substrate size and material.
In an embodiment, the lithographic apparatus is highly flexible. In an embodiment, the lithographic apparatus is scalable to substrates of different sizes, types and characteristics. In an embodiment, the lithographic apparatus has a virtually unlimited field size. Thus, the lithographic apparatus can enable multiple applications (e.g., IC, flat panel display, packaging, etc.) with a single lithographic apparatus or using multiple lithographic apparatus using a largely common lithographic apparatus platform. In an embodiment, the lithographic apparatus allows automated job generation to provide for flexible manufacture. In an embodiment, the lithographic apparatus provides 3D integration.
In an embodiment, the lithographic apparatus is low cost. In an embodiment, only common off-the-shelf components are used (e.g., radiation emitting diodes, a simple movable substrate holder, and a lens array). In an embodiment, pixel-grid imaging is used to enable simple projection optics. In an embodiment, a substrate holder having a single scan direction is used to reduce cost and/or reduce complexity.
In an embodiment, the patterning device 104 comprises a plurality of individually controllable elements 102 to modulate radiation to apply a pattern to beam 110. In an embodiment, the position of the plurality of individually controllable elements 102 can be fixed relative to projection system 108. However, in an alternative arrangement, a plurality of individually controllable elements 102 may be connected to a positioning device (not shown) to accurately position one or more of them in accordance with certain parameters (e.g., with respect to projection system 108).
In an embodiment, the patterning device 104 is a self-emissive contrast device. Such a patterning device 104 obviates the need for a radiation system, which can reduce, for example, cost and size of the lithographic apparatus. For example, each of the individually controllable elements 102 is a radiation emitting diode, such a light emitting diode (LED), an organic LED (OLED), a polymer LED (PLED), or a laser diode (e.g., solid state laser diode). In an embodiment, each of the individually controllable elements 102 is a laser diode. In an embodiment, each of the individually controllable elements 102 is a blue-violet laser diode (e.g., Sanyo model no. DL-3146-151). Such diodes are supplied by companies such as Sanyo, Nichia, Osram, and Nitride. In an embodiment, the diode emits radiation having a wavelength of about 365 nm or about 405 nm. In an embodiment, the diode can provide an output power selected from the range of 0.5-100 mW. In an embodiment, the size of laser diode (naked die) is selected from the range of 250-600 micrometers. In an embodiment, the laser diode has an emission area selected from the range of 1-5 micrometers. In an embodiment, the laser diode has a divergence angle selected from the range of 7-44 degrees. In an embodiment, the diode may be modulated at 100 MHz.
In an embodiment, the self-emissive contrast device comprises more individually addressable elements 102 than needed to allow a “redundant” individually controllable element 102 to be used if another individually controllable element 102 fails to operate or doesn't operate properly.
In an embodiment, the individually controllable elements 102 of a self-emissive contrast device are operated in the steep part of the power/forward current curve of the individually controllable elements 102 (e.g., a laser diode). This may be more efficient and lead to less power consumption/heat. In an embodiment, the optical output per individually controllable element, when in use, is at least 1 mW, e.g. at least 10 mW, at least 25 mW, at least 50 mW, at least 100 mW, or at least 200 mW. In an embodiment, the optical output per individually controllable element, when in use, is less than 300 mW, less than 250 mW, less than 200 mW, less than 150 mW, less than 100 mW, less than 50 mW, less than 25 mW, or less than 10 mW. In an embodiment, the power consumption per programmable patterning device, when in use, to operate the individually controllable elements is less than 10 kW, e.g. less than 5 kW, less than 1 kW, or less than 0.5 kW. In an embodiment, the power consumption per programmable patterning device, when in use, to operate the individually controllable elements is at least 100 W, e.g. at least 300 W, at least 500 W, or at least 1 kW.
The lithographic apparatus 100 comprises an object holder 106. In this embodiment, the object holder comprises an object table 106 to hold a substrate 114 (e.g., a resist-coated silicon wafer or glass substrate). The object table 106 may be movable and be connected to a positioning device 116 to accurately position substrate 114 in accordance with certain parameters. For example, positioning device 116 may accurately position substrate 114 with respect to projection system 108 and/or the patterning device 104. In an embodiment, movement of object table 106 may be realized with a positioning device 116 comprising a long-stroke module (coarse positioning) and optionally a short-stroke module (fine positioning), which are not explicitly depicted in
Projection system 108 (e.g., a quartz and/or CaF2 lens system or a catadioptric system comprising lens elements made from such materials, or a mirror system) can be used to project the patterned beam modulated by the individually controllable elements 102 onto a target portion 120 (e.g., one or more dies) of substrate 114. Projection system 108 may project image the pattern provided by the plurality of individually controllable elements 102 such that the pattern is coherently formed on the substrate 114. Alternatively, projection system 108 may project images of secondary sources for which the elements of the plurality of individually controllable elements 102 act as shutters.
In this respect, the projection system may comprise a focusing element, or a plurality of focusing elements (herein referred to generically as a lens array) e.g., a micro-lens array (known as an MLA) or a Fresnel lens array, e.g. to form the secondary sources and to image spots onto the substrate 114. In an embodiment, the lens array (e.g., MLA) comprises at least 10 focusing elements, e.g. at least 100 focusing elements, at least 1,000 focusing elements, at least 10,000 focusing elements, at least 100,000 focusing elements, or at least 1,000,000 focusing elements. In an embodiment, the number of individually controllable elements in the patterning device is equal to or greater than the number of focusing elements in the lens array. In an embodiment, the lens array comprises a focusing element that is optically associated with one or more of the individually controllable elements in the array of individually controllable elements, e.g. with only one of the individually controllable elements in the array of individually controllable elements, or with 2 or more of the individually controllable elements in the array of individually controllable elements, e.g., 3 or more, 5 or more, 10 or more, 20 or more, 25 or more, 35 or more, or 50 or more; in an embodiment, the focusing element is optically associated with less than 5,000 individually controllable elements, e.g. less than 2,500, less than 1,000, less than 500, or less than 100. In an embodiment, the lens array comprises more than one focusing element (e.g. more than 1,000, the majority, or about all) that is optically associated with one or more of the individually controllable elements in the array of individually controllable elements.
In an embodiment, the lens array is movable at least in the direction to and away from the substrate, e.g. with the use of one or more actuators. Being able to move the lens array to and away from the substrate allows, e.g., for focus adjustment without having to move the substrate. In an embodiment, individual lens element in the lens array, for instance each individual lens element in the lens array, are movable at least in the direction to and away from the substrate (e.g. for local focus adjustments on non-flat substrates or to bring each optical column into the same focus distance).
In an embodiment, the lens array comprises plastic focusing elements (which may be easy to make, e.g. injection molding, and/or affordable), where, for example, the wavelength of the radiation is greater than or equal to about 400 nm (e.g. 405 nm). In an embodiment, the wavelength of the radiation is selected from the range of about 400 nm-500 nm. In an embodiment, the lens array comprises quartz focusing elements. In an embodiment, each or a plurality of the focusing elements may be an asymmetrical lens. The asymmetry may be the same for each of the plurality of focusing elements or may be different for one or more focusing elements of a plurality of focusing elements than for one or more different focusing elements of a plurality of focusing elements. An asymmetrical lens may facilitate converting an oval radiation output into a circular projected spot, or vice versa.
In an embodiment, the focusing element has a high numerical aperture (NA) that is arranged to project radiation onto the substrate out of the focal point to obtain low NA for system. A higher NA lens may be more economic, prevalent and/or better quality than an available low NA lens. In an embodiment, low NA is less than or equal to 0.3, in an embodiment 0.18, 0.15 or less. Accordingly, a higher NA lens has a NA greater than the design NA for the system, for example, greater than 0.3, greater than 0.18, or greater than 0.15.
While, in an embodiment, the projection system 108 is separate from the patterning device 104, it need not be. The projection system 108 may be integral with the patterning device 108. For example, a lens array block or plate may be attached to (integral with) with a patterning device 104. In an embodiment, the lens array may be in the form of individual spatially separated lenslets, each lenslet attached to (integral with) with an individually addressable element of the patterning device 104 as discussed in more detail below.
Optionally, the lithographic apparatus may comprise a radiation system to supply radiation (e.g., ultraviolet (UV) radiation) to the plurality of individually controllable elements 102. If the patterning device is a radiation source itself, e.g. a laser diode array or a LED array, the lithographic apparatus may be designed without a radiation system, i.e. without a radiation source other than the patterning device itself, or at least a simplified radiation system.
The radiation system includes an illumination system (illuminator) configured to receive radiation from a radiation source. The illumination system includes one or more of the following elements: a radiation delivery system (e.g., suitable directing mirrors), a radiation conditioning device (e.g., a beam expander), an adjusting device to set the angular intensity distribution of the radiation (generally, at least the outer and/or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted), an integrator, and/or a condenser. The illumination system may be used to condition the radiation that will be provided to the individually controllable elements 102 to have a desired uniformity and intensity distribution in its cross-section. The illumination system may be arranged to divide radiation into a plurality of sub-beams that may, for example, each be associated with one or more of the plurality of the individually controllable elements. A two-dimensional diffraction grating may, for example, be used to divide the radiation into sub-beams. In the present description, the terms “beam of radiation” and “radiation beam” encompass, but are not limited to, the situation in which the beam is comprised of a plurality of such sub-beams of radiation.
The radiation system may also include a radiation source (e.g., an excimer laser) to produce the radiation for supply to or by the plurality of individually controllable elements 102. The radiation source and the lithographic apparatus 100 may be separate entities, for example when the radiation source is an excimer laser. In such cases, the radiation source is not considered to form part of the lithographic apparatus 100 and the radiation is passed from the source to the illuminator. In other cases the radiation source may be an integral part of the lithographic apparatus 100, for example when the source is a mercury lamp. Both of these scenarios are contemplated within the scope of the present invention.
In an embodiment, the radiation source, which in an embodiment may be the plurality of individually controllable elements 102, can provide radiation having a wavelength of at least 5 nm, e.g. at least 10 nm, at least 50 nm, at least 100 nm, at least 150 nm, at least 175 nm, at least 200 nm, at least 250 nm, at least 275 nm, at least 300 nm, at least 325 nm, at least 350 nm, or at least 360 nm. In an embodiment, the radiation has a wavelength of at most 450 nm, e.g. at most 425 nm, at most 375 nm, at most 360 nm, at most 325 nm, at most 275 nm, at most 250 nm, at most 225 nm, at most 200 nm, or at most 175 nm. In an embodiment, the radiation has a wavelength including 436 nm, 405 nm, 365 nm, 355 nm, 248 nm, 193 nm, 157 nm, 126 nm, and/or 13.5 nm. In an embodiment, the radiation includes a wavelength of around 365 nm or around 355 nm. In an embodiment, the radiation includes a broad band of wavelengths, for example encompassing 365 nm, 405 nm and 436 nm. A 355 nm laser source could be used. In an embodiment, the radiation has a wavelength of about 405 nm.
In an embodiment, radiation is directed from the illumination system at the patterning device 104 at an angle between 0 and 90°, e.g. between 5 and 85°, between 15 and 75°, between 25 and 65°, or between 35 and 55°. The radiation from the illumination system may be provided directly to the patterning device 104. In an alternative embodiment, radiation may be directed from the illumination system to the patterning device 104 by means of a beam splitter (not shown) configured such that the radiation is initially reflected by the beam splitter and directed to the patterning device 104. The patterning device 104 modulates the beam and reflects it back to the beam splitter which transmits the modulated beam toward the substrate 114. However, alternative arrangements may be used to direct radiation to the patterning device 104 and subsequently to the substrate 114. In particular, an illumination system arrangement may not be required if a transmissive patterning device 104 (e.g. a LCD array) is used or the patterning device 104 is self-emissive (e.g., a plurality of diodes).
In operation of the lithographic apparatus 100, where the patterning device 104 is not radiation emissive (e.g., comprising LEDs), radiation is incident on the patterning device 104 (e.g., a plurality of individually controllable elements) from a radiation system (illumination system and/or radiation source) and is modulated by the patterning device 104. The patterned beam 110, after having been created by the plurality of individually controllable elements 102, passes through projection system 108, which focuses beam 110 onto a target portion 120 of the substrate 114.
With the aid of positioning device 116 (and optionally a position sensor 134 on a base 136 (e.g., an interferometric measuring device that receives an interferometric beam 138, a linear encoder or a capacitive sensor)), substrate 114 can be moved accurately, e.g., so as to position different target portions 120 in the path of beam 110. Where used, the positioning device for the plurality of individually controllable elements 102 can be used to accurately correct the position of the plurality of individually controllable elements 102 with respect to the path of beam 110, e.g., during a scan.
Although lithography apparatus 100 according to an embodiment of the invention is herein described as being for exposing a resist on a substrate, apparatus 100 may be used to project a patterned beam 110 for use in resistless lithography.
The lithographic apparatus 100 may be of a reflective type (e.g. employing reflective individually controllable elements). Alternatively, the apparatus may be of a transmissive type (e.g. employing transmissive individually controllable elements).
The depicted apparatus 100 can be used in one or more modes e.g.:
1. In step mode, the individually controllable elements 102 and the substrate 114 are kept essentially stationary, while an entire patterned radiation beam 110 is projected onto a target portion 120 at one go (i.e. a single static exposure). The substrate 114 is then shifted in the X- and/or Y-direction so that a different target portion 120 can be exposed to the patterned radiation beam 110. In step mode, the maximum size of the exposure field limits the size of the target portion 120 imaged in a single static exposure.
2. In scan mode, the individually controllable elements 102 and the substrate 114 are scanned synchronously while a pattern radiation beam 110 is projected onto a target portion 120 (i.e. a single dynamic exposure). The velocity and direction of the substrate relative to the individually controllable elements may be determined by the (de-) magnification and image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width (in the non-scanning direction) of the target portion in a single dynamic exposure, whereas the length of the scanning motion determines the height (in the scanning direction) of the target portion.
3. In pulse mode, the individually controllable elements 102 are kept essentially stationary and the entire pattern is projected onto a target portion 120 of the substrate 114 using pulsing (e.g., provided by a pulsed radiation source or by pulsing the individually controllable elements). The substrate 114 is moved with an essentially constant speed such that the patterned beam 110 is caused to scan a line across the substrate 114. The pattern provided by the individually controllable elements is updated as required between pulses and the pulses are timed such that successive target portions 120 are exposed at the required locations on the substrate 114. Consequently, patterned beam 110 can scan across the substrate 114 to expose the complete pattern for a strip of the substrate 114. The process is repeated until the complete substrate 114 has been exposed line by line.
4. In continuous scan mode, essentially the same as pulse mode except that the substrate 114 is scanned relative to the modulated beam of radiation B at a substantially constant speed and the pattern on the array of individually controllable elements is updated as the patterned beam 110 scans across the substrate 114 and exposes it. A substantially constant radiation source or a pulsed radiation source, synchronized to the updating of the pattern on the array of individually controllable elements may be used.
Combinations and/or variations on the above described modes of use or entirely different modes of use may also be employed.
The lithographic apparatus 100 further comprises a plurality of individually addressable elements 102 arranged on a frame 160. Frame 160 may be mechanically isolated from the substrate table 106 and its positioning device 116. Mechanical isolation may be provided, for example, by connecting the frame 160 to ground or a firm base separately from the frame for the substrate table 106 and/or its positioning device 116. In addition or alternatively, dampers may be provided between frame 160 and the structure to which it is connected, whether that structure is ground, a firm base or a frame supporting the substrate table 106 and/or its positioning device 116.
In this embodiment, each of the individually addressable elements 102 is a radiation emitting diode, e.g., a blue-violet laser diode. As shown in
Each of the arrays of individually addressable elements 102 may be part of an individual optical engine component, which may be manufactured as a unit for easy replication. Moreover, frame 160 may be configured to be expandable and configurable to easily adopt any number of such optical engine components. The optical engine component may comprise a combination of an array of individually addressable elements 102 and lens array 170. For example, in
Further, the lithographic apparatus 100 comprises an alignment sensor 150. The alignment sensor is used to determine alignment between the substrate 114 and, for example, the individually addressable elements 102 before and/or during exposure of the substrate 114. The results of the alignment sensor 150 can be used by a controller of the lithographic apparatus 100 to control, for example, the positioning device 116 to position the substrate table 106 to improve alignment. In addition or alternatively, the controller may control, for example, a positioning device associated with the individually addressable elements 102 to position one or more of the individually addressable elements 102 to improve alignment and/or to control a deflector 112 associated with the individually addressable elements 102 to position one or more of the beams to improve alignment. In an embodiment, the alignment sensor 150 may include pattern recognition functionality/software to perform alignment.
The lithographic apparatus 100, in addition or alternatively, comprises a level sensor 150. The level sensor 150 is used to determine whether the substrate 106 is level with respect to the projection of the pattern from the individually addressable elements 102. The level sensor 150 can determine level before and/or during exposure of the substrate 114. The results of the level sensor 150 can be used by a controller of the lithographic apparatus 100 to control, for example, the positioning device 116 to position the substrate table 106 to improve leveling. In addition or alternatively, the controller may control, for example, a positioning device associated with a projection system 108 (e.g., a lens array) to position an element of the projection system 108 (e.g., a lens array) to improve leveling. In an embodiment, the level sensor may operate by projecting an ultrasonic beam at the substrate 106 and/or operate by projecting an electromagnetic beam of radiation at the substrate 106.
In an embodiment, results from the alignment sensor and/or the level sensor may be used to alter the pattern provided by the individually addressable elements 102. The pattern may be altered to correct, for example, distortion, which may arise from, e.g., optics (if any) between the individually addressable elements 102 and the substrate 114, irregularities in the positioning of the substrate 114, unevenness of the substrate 114, etc. Thus, results from the alignment sensor and/or the level sensor can be used to alter the projected pattern to effect a non-linear distortion correction. Non-linear distortion correction may be useful, for example, for flexible displays, which may not have consistent linear or non-linear distortion.
In operation of the lithographic apparatus 100, a substrate 114 is loaded onto the substrate table 106 using, for example, a robot handler (not shown). The substrate 114 is then displaced in the X-direction under the frame 160 and the individually addressable elements 102. The substrate 114 is measured by the level sensor and/or the alignment sensor 150 and then is exposed to a pattern using individually addressable elements 102. For example, the substrate 114 is scanned through the focal plane (image plane) of the projection system 108, while the sub-beams, and hence the image spots S (see, e.g.,
In an embodiment, the substrate 114 may be scanned completely in the positive X-direction and then scanned completely in the negative X-direction. In such an embodiment, an additional level sensor and/or alignment sensor 150 on the opposite side of the individually addressable elements 102 may be required for the negative X-direction scan.
The lithographic apparatus 100 further comprises a plurality of individually addressable elements 102 arranged on a frame 160. In this embodiment, each of the individually addressable elements 102 is a radiation emitting diode, e.g., a blue-violet laser diode. As shown in
In operation of the lithographic apparatus 100, a panel display substrate 114 is loaded onto the substrate table 106 using, for example, a robot handler (not shown). The substrate 114 is then displaced in the X-direction under the frame 160 and the individually addressable elements 102. The substrate 114 is measured by the level sensor and/or the alignment sensor 150 and then is exposed to a pattern using individually addressable elements 102. The individually addressable elements 102 may be operated, for example, to provide pixel-grid imaging as discussed herein.
The lithographic apparatus may also comprise an object holder having an object table 106 over which a substrate 114 is moved. The substrate 114 is flexible and is rolled onto a roll connected to positioning device 116, which may be a motor to turn the roll. In an embodiment, the substrate 114 may, in addition or alternatively, be rolled from a roll connected to positioning device 116, which may be a motor to turn the roll. In an embodiment, there are at least two rolls, one from which the substrate is rolled and another onto which the substrate is rolled. In an embodiment, object table 106 need not be provided if, for example, substrate 114 is stiff enough between the rolls. In such a case, there would still be an object holder, e.g., one or more rolls. In an embodiment, the lithographic apparatus can provide substrate carrier-less (e.g., carrier-less-foil (CLF)) and/or roll to roll manufacturing. In an embodiment, the lithographic apparatus can provide sheet to sheet manufacturing.
In operation of the lithographic apparatus 100, flexible substrate 114 is rolled onto, and/or from a roll, in the X-direction under the frame 160 and the individually addressable elements 102. The substrate 114 is measured by the level sensor and/or the alignment sensor 150 and then is exposed to a pattern using individually addressable elements 102. The individually addressable elements 102 may be operated, for example, to provide pixel-grid imaging as discussed herein.
The deflected beam from the deflector 112 is received by the projection system 108. The projection system 108 comprises two lenses 124, 170. The first lens 124, a field lens, is arranged to receive the modulated radiation beam 110 from the patterning device 104. In an embodiment, the lens 124 is located in an aperture stop 126. The radiation beam 110 diverges from field lens 124 and is received by a second lens 170, an imaging lens. The lens 170 focuses the beam 110 onto the substrate 114. In an embodiment, the focal plane of the lens 124 at a first focal distance 128 is substantially optically conjugate with the back focal plane of the lens 170 at a second focal distance 130. In an embodiment, the lens 170 can provide a NA of 0.15 or 0.18. In an embodiment, the lens 124 and/or the lens 170 may be moved in up to 6 degrees of freedom (e.g., in the X-Y-Z directions) using an actuator.
In an embodiment, each individually addressable element 102 has an associated deflector 112 and associated lens 170. Accordingly, referring to
In an embodiment, there may not be number correspondence between the various elements, such as individually addressable elements 102 and deflectors 112. For example, referring to
As shown in
In an embodiment, the projection system 108 can be a 1:1 projection system in that the array spacing of the image spots on the substrate 114 is the same as the array spacing of the pixels of the patterning device 104. To provide improved resolution, the image spots can be much smaller than the pixels of the patterning device 104.
Referring to
As discussed above, the deflector 112 facilitates deflection of the radiation beam from the individually addressable element 102 in the X- and/or Y-direction. In other words, this type of deflector can scan the beam 110 or point the beam 110 towards a specific location on the substrate 114. In an embodiment, the deflector 112 may deflect the radiation in only the Y-direction or only the X-direction. In an embodiment, the deflector 112 may deflect the radiation in both X- and Y-directions. In an embodiment, sequential deflectors 112, each capable of deflecting the radiation in only one, but different, direction, are capable of deflecting the radiation in both the X- and Y-directions. For example, two of the same type of deflector may be mounted perpendicularly to and underneath each other, resulting in deflection in both X- and Y-directions. An example of such a deflector 112 that deflects the radiation in both X- and Y-directions is depicted in
In an embodiment, the deflector 112 may be a mechanical (i.e., galvanometer-type), an electro-optic, and/or acousto-optic deflector. A mechanical deflector tends to provide the largest number of resolvable radiation spots (i.e., a resolvable spot means that the beam is deflected by an angle equal to its own angular spread), but tends to be slowest in terms of spot scan rate. An electro-optic deflector tends to be the fastest in terms of spot scan rate, but tends to have the smallest number of resolvable radiation spots.
In an embodiment, the deflector 112 is an electro-optical deflector. An electro-optical deflector may provide a switching speed of up to a few nanoseconds. In an embodiment, the electro-optical deflector may provide deflection angles of +/−15 degrees. In an embodiment, this may yield about 600 radiation spots for an input beam divergence of 0.05 degrees. In an embodiment, use of an electro-optical deflector may avoid having a fast moving mechanical part for radiation deflection. In an embodiment, there may be no moving optical elements between the radiation source 102 and the substrate 114.
The electro-optical deflector may comprise an optically transparent piezo material. Thus, in an embodiment, a radiation beam is steered due to a potential difference applied over the material. For example, when a potential difference is applied across such an optically transparent material, the index of refraction of the material changes, which changes the direction of beam propagation (i.e., the radiation beam can be deflected). In an embodiment, the material is selected from the following: LiNbO3, LiTaO3, KH2PO4 (KDP), or NH4H2PO4 (ADP). LiTaO3 is transparent at the 405 nm wavelength.
Referring to
In an embodiment where the electro-optical element 112 is situated under angle with respect to the beam 110, there may be radiation loss due to reflection under the grazing incidence. Thus, referring to
In an embodiment, the deflector 112 may deflect the radiation in both X- and Y-directions. Referring to
The deflection by the electro-optical deflector 112 may be limited. Therefore enhancement may be used. This is illustrated in
An additional or alternative way to increase the deflection angle (and thus the number of resolvable points) is to use a plurality of prisms in sequence and/or to utilize the total internal reflection effect. Referring to
Referring to
In an embodiment, referring to
In an embodiment, the refractive index change is largest at one electrode 184 (e.g., the anode) and smallest at the other electrode 184 (e.g., the cathode). Reversing the potential difference also reverses the direction of deflection (e.g. from +x to −x). Further, deflection is in principle possible in two different directions if two potential differences are applied (e.g., deflection in X- and Y-directions for a beam propagating in the Z-direction). Thus, a compact two-dimensional deflector may be realized.
Using, for example, KTN, a smaller deflector 112 may be realized thus reducing the chance of distortion of the beam profile due to the length of the deflector 112 along the beam propagation path. For example, a deflector 112 of 5×5×0.5 mm may be provided. Further, high deflection angles may be obtained, for example 150 mrad @ 250 V. Such a deflector 112 may also be modulated at MHz frequency, has high transparency at, for example, 532 nm, ˜800 nm and 1064 nm, and has a high damage threshold of, for example, >500 MW/cm2 @1064 nm.
Referring back to
As discussed above and referring to, for example,
Referring to
In an embodiment, the exposure strategy varies from that described above in that the diodes 102 project a two-dimensional array of spots on the substrate 114. The exposure sequence would be, for example, that the first rectangular area 1.1 is fully exposed by the diodes 102, then rectangle 2.2, and then rectangle 3.3, and then to rectangle 1.2, rectangle 2.2 and so on. To improve the quality of the deflected beam 110, the deflector 112 is ramped up only between diode pulses. This type of exposure strategy can be called “stepper type”.
In an embodiment, a substrate of nominal 1×1 m size may be exposed in about 10 seconds using 1000 diodes 102 with a sweep time of about 10 μs, a diode pulse duration of about 10 ns, an exposure grid and spot size of 1 μm, a number of resolvable points of the deflector 112 of about 1000, and a substrate 114 scanning speed of 0.1 m/s. In an embodiment, an image field of 0.4 mm (shown by the double headed arrow in
Thus, in an embodiment, the full exposure mode involves modulation by the individually addressable elements 102. In other words, the individually addressable elements 102 are only a limited time “on”. The deflector 112 quickly deflects the beamlets 110 to cause exposure of the pattern as the intensity of the beamlets 110 is modulated and the substrate 114 is moved in the X-direction. In an embodiment, the deflector 112 causes deflection in the Y-direction but no deflection in the X-direction. Thus, referring to
However, some devices and structures have only limited pattern density and so less than, for example, 15% of the area has to be exposed during fabrication. For example, pattern density may be 4% of a surface (e.g., an active matrix flat panel display may have 3 micron lines for 80 micron sub-pixel width). Thus, with a pattern density of 4%, up to 96% of the radiation may not be used in an arrangement where each pixel on a substrate is addressed by a maskless system (e.g., all pixels on the substrate are addressed and for each pixel the radiation intensity is adjusted to create the pattern). In other words, there is an overcapacity of radiation.
Accordingly, in a second mode, efficient exposure mode, only pixels on a substrate are addressed that have to be exposed thus reducing the amount of radiation that may be wasted. Thus, there may be reduced radiation power and reduced cost. Further, such an exposure mode may reduce the complexity of the datapath and reduce thermal load in the system.
To address only pixels on a substrate that need to be exposed, a contrast device may be provided that directs the beam or beamlet to the desired position. In an embodiment, the beam or beamlets is directed by a deflector 112 to only the spots on the substrate that need to be exposed. In an embodiment, the deflector 112 is configured to deflect a beamlet in both X- and Y-directions to position the spot only on a pixel on the substrate that needs to be exposed. When a beamlet is not needed, it can be deflected towards a beam dump. For example, the beam dump may be located at the field lens 124 and may be the aperture stop 126. In the efficient exposure mode, an individual radiation source (such as a laser diode) may be provided for each beamlet or a single radiation source may be used to form multiple beamlets.
Thus, in an embodiment, the efficient exposure mode does not necessarily involve modulation by the individually addressable elements 102. In other words, the individually addressable elements 102 may be “always on”, i.e., individually addressable elements may not have their intensity decreased during exposure. The deflector 112 quickly deflects the beamlets 110 to cause exposure of the pattern (and thus modulation) and the substrate 114 is moved in the X-direction. In an embodiment, the deflector 112 causes deflection in the X- and Y-directions (while the substrate still moves in the X-direction). Thus, referring to
Referring to
In an embodiment, an efficient exposure mode apparatus may comprise multiple radiation sources. For example, there may be a plurality of laser diodes having a 2.3 mW output power per laser diode for a 6% pattern density. In an embodiment, an efficient exposure mode apparatus may comprise a single radiation source. For example, there may be a single radiation source of 690 mW to produce 300 spots across a 120 mm exposure width.
Further, while the description herein has primarily focused on exposing a radiation-sensitive surface of a substrate, the apparatus, systems and methods described herein may additionally or alternatively be applied to deposit a material on a substrate, or to remove material of (e.g., on or making up) a substrate, or both material deposition and removal. For example, the beam described herein may be used to cause metal deposition on a substrate and/or ablation of a substrate. In an embodiment, an apparatus may provide a combination of lithography using a radiation-sensitive surface (herein referred to as photolithography) and material deposition using the beam described herein. In an embodiment, an apparatus may provide a combination of material deposition and removal using the beam described herein. In an embodiment, an apparatus may provide photolithography, material deposition and material removal using the beam described herein.
Advantageously, the apparatus, methods and systems described herein may provide a single tool to provide much, if not all, processing of a device or other structure. Production may become more flexible with such a tool. Capital expense may be reduced by reduced usage of separate tools to provide particular processing (e.g., metal deposition and ablation may be combined into a single tool, rather than having specialized tools for each process).
Further, in appropriate circumstances, new processes may be adopted to eliminate one or more production steps or substitute one or more production steps with one or more other production steps to lead to a production process that is quicker and/or more efficient, etc. As an example, the production of a flat panel display traditionally involves production of a number of layers using photolithography, deposition and etching. In a more specific example, production of a backplane for a flat panel display may involve the creation of 5 layers, each involving photolithography, deposition and etching. Such production may involve 5 process steps and often 5 tools to define a metal pattern. The steps include metal sheet deposition, photo resist coating, photolithography and developing of the resist, etching of the metal using the developed resist, and stripping of the resist after etching. Thus, not only is there a significant amount of capital (e.g., in the form of tools), there is also a significant amount of inefficient material usage. For example in defining an active matrix flat panel display, photoresist may be used to cover a 3 m×3 m glass plate, which photoresist is later completely washed away. Similarly, copper and/or other metals are deposited on the full glass plate and later up to 95% of which is washed away. Further, chemicals are used to etch or strip the above materials.
Thus, technical disruption of such production could be achieved by consolidating one or more reductive steps into an additive step. Thus, rather than a combination of photolithography, deposition and etching steps, a material deposition step may be used to additively create a structure that would typically be created by eliminating material. Direct material deposition could eliminate several reductive process steps typically used in flat panel display manufacture. Additionally and alternatively, ablation may be used to eliminate material without, for example, the need for resist coating and developing. Consequently, such laser induced processing—material deposition and/or removal—is a natural extension of photolithography, since beam energy is used to affect a material.
In an embodiment, for example, a single apparatus may be used for most, if not all, layers of flat panel display production. For example, the apparatus may perform maskless photolithography (if needed), laser beam induced deposition (e.g., of a metal pattern of a liquid crystal (e.g., active matrix) display), and laser beam ablation (e.g., of an indium tin oxide (ITO) conductive layer) to produce a display panel.
First, then, a description of material deposition is provided and then a description of material removal. In an embodiment, the material deposition involves a laser induced forward transfer (LIFT) of material (e.g., metal) onto a substrate, which is a method to deposit material directly on the substrate without photolithography. In an embodiment, the material may be aluminum, chromium, molybdenum, copper, or any combination thereof.
The apparatus, process and system for such deposition may be very similar to a lithography tool or process with the main difference from a photolithography tool or process being the application of the beam onto a material donor plate rather than directly onto the substrate.
Referring to
In an embodiment, one or more short pulses are used to cause the transfer of the donor material. In an embodiment, the pulses may be a few picoseconds or femto-seconds long to obtain quasi one dimensional forward heat and mass transfer of molten material. Such short pulses facilitate little to no lateral heat flow in the material layer 204 and thus little or no thermal load on the donor structure 208. The short pulses enable rapid melting and forward acceleration of the material (e.g., vaporized material, such as metal, would lose its forward directionality leading to a splattering deposition). The short pulses enable heating of the material to just above the heating temperature but below the vaporization temperature. For example, for aluminum and referring to
In an embodiment, through the use of a laser pulse, an amount of material (e.g., metal) is transferred from the donor structure 208 to the substrate 114 in the form of 100-1000 nm droplets. In an embodiment, the donor material comprises or consists essentially of a metal. In an embodiment, the metal is aluminum. In an embodiment, the donor material may comprise a mixture of a metal (or other patterning material) and a material to alter the surface tension of the mixture compared to if the donor material only had the metal (or patterning material). Such material to alter the surface tension would improve the ability of the donor material to fill a hole of an existing donor material layer 204 and/or to provide a smooth filling of a hole of an existing donor material layer 204. For example, the material to alter the surface tension may be a paint or the donor material may itself be a paint. In an embodiment, the material to alter the surface tension may comprise a non-ionic surfactant, such as octylphenol ethoxylate, (fluoro)aliphatic polyoxyethylene, and/or poly(dimethyl)siloxane—polyethylene glycol, and/or an ionic surfactant, such as ammonium lauryl sulfate (cationic), benzalkonium chloride (anionic) and/or 3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate (zwitter ionic).
In an embodiment, the material layer 204 is in the form of a film. For example, the material layer 204 may be at least 0.05 mm, at least 0.1 mm, at least 0.2 mm, at least 0.5 mm, at least 1 mm, or at least 2 mm, at least 3 mm or at least 5 mm. The film may be less or equal to 20 mm, less than or equal to 10 mm, or less than or equal to 5 mm. In an embodiment, the film is attached to another body or layer. As discussed above, the body or layer may be a glass or a plastic. For example, the body or layer may be quartz or calcium fluoride. The body or layer may be in the form a film. For example, the body or layer may be at least 0.5 mm, at least 1 mm, at least 2 mm, at least 5 mm, at least 1 cm, or at least 5 cm. The film may be less or equal to 20 cm, less than or equal to 10 cm, or less than or equal to 5 cm. Thus, in an embodiment, the donor structure 208 may comprise a thin film of plastic (or other material) on which a thin layer of donor material, such as aluminum, is provided. Or, in an embodiment, the donor structure 208 may be only a metal film. Where the material layer 204 is attached to another body or layer, the beam may not cause a hole to form in the body or layer but cause a hole in the material layer 204. In an embodiment, the beam may cause a hole to form in the body or layer and also in the material layer (and thus a hole all the way through the donor structure 208 is formed). In an embodiment, where the donor structure 208 is only a metal film, the beam may cause a hole to form all the way through the donor structure 208.
As discussed below, the donor material may be in the form of a powder or particles in an electrostatic or electromagnetic embodiment discussed below. Accordingly, the powder or particles will be able to hold a certain charge or have a certain polarity. The body or layer on which the donor material powder or particles is retained may similarly be able to hold a certain charge or have a certain polarity in order to retain the powder or particles.
An embodiment of an apparatus to provide material deposition is depicted in
As described above, the apparatus may be configured to provide a combination of photolithography, material deposition and/or material removal. A controller 218 may control the switch between the mode of photolithography and material deposition, between material deposition and material removal, etc. For example, to switch between photolithography and material deposition, the controller 218 may control the apparatus to change the appropriate optical and beam settings between photolithography and material deposition (for example, increase power and/or shorten pulse length for material deposition) and, in certain circumstances, cause the donor structure 208 to be inserted into and/or removed the beam path. For example, to switch between material removal and material deposition, the controller 218 may control the apparatus to change the appropriate optical and beam settings between material removal and material deposition (for example, increase beam power) and, in certain circumstances, cause the donor structure 208 to be inserted into and/or removed the beam path.
Referring to
In an embodiment, the donor structure 208 has a same size (e.g., diameter, width, length, width and length, etc.) and optionally the same shape as the substrate 114 and thus may be introduced using a substrate handler (e.g., a robot). The donor structure 208 may be stored, for example, in its own storage unit or the storage unit of the substrate 114 when it is not being used, e.g., when the apparatus is used in photolithography and/or ablation mode. In an embodiment, the donor structure 208 has width of 3 meters.
In an embodiment, the donor structure 208 may be supported on the substrate 114, substrate table 106, positioning device 116, or its own positioning device (e.g., an actuator). For example, referring to
In an embodiment, referring to
In an embodiment, the donor structure 208 is supported from above at least in part by the frame 210. To facilitate movement of the donor structure 208, the donor structure 208 is supported, in an embodiment, by a pre-stressed gas (e.g., air) bearing 212 of the frame 210. In this bearing 212, a combination of underpressure 214 (e.g., vacuum suction) and overpressure 216 (e.g., pressurized gas) is applied. In an embodiment, the underpressure 214 and overpressure 216 are arranged in a checkerboard pattern of respective inlets and outlets. The underpressure 214 can be used to compensate gravity and hold the donor structure 208 in position; the overpressure 216 is used to help prevent the donor structure 208 from adhering to the frame 210 and thus permit donor structure 208 to move. Referring to
While, in certain embodiments described above (and below), the donor structure 208 is shown as being displaced in a direction substantially parallel to the scanning translation direction of the substrate 114, this need not be the case. For example, additionally or alternatively, the donor structure 208 may be displaced substantially perpendicularly to the scanning direction (as shown, for example, in
In an embodiment, the donor structure 208 is refreshed to enable continued material deposition. In an embodiment, after production of a substrate with a certain pattern, the donor structure 208 is refreshed. This is because the donor structure 208 is the negative of the pattern deposited on the substrate 114 since the donor material is transferred from the donor structure 208 to the substrate 114. Thus, transfer of the same pattern again from the donor structure 208 may not feasible without refreshment to provide a new substantially uniform layer of donor material. In an embodiment, the apparatus may comprise a controller 218 configured to increase or maximize use of the donor structure 208 by, for example, causing relative displacement between the donor structure 208 and the substrate 114 to enable projection of the beamlets on unused areas of the donor structure 208. Similarly, the controller 218 may enable the beamlets to be projected in different patterns to make further use of the donor structure 208 without refreshment.
In an embodiment, the donor structure 208 refreshment comprises substituting a new donor structure 208 for a donor structure 208 used during exposure. In an embodiment, the donor structure 208 refreshment comprises regenerating the donor material on the donor structure 208 (since only a few % (e.g., up to about 6%) of the donor material layer 204 is transferred to the substrate). Regeneration of the donor material layer 204 on the donor structure 208 may save cost.
In an embodiment, refreshment of the donor structure 208 may be accomplished in several example ways. In an embodiment, the donor structure 208 may be replaced by a “fresh” one and a new layer of donor material is applied to the used donor structure 208 off-line. For example, the donor structure 208 may be changed with the load-unload of a new substrate 114. The donor structure 208 may have a similar size, and optionally shape, as the substrate so it may be handled with the same handler used to load-unload the substrate. In an embodiment, the “used” donor structure 208 may be disposed.
In an embodiment, referring to
Every time a “new” donor structure 208 is needed to pattern the substrate 114 a “fresh” part of the membrane from, for example, the roll is used. So, in an embodiment, the apparatus may have two rolls—one with “fresh” donor structure 208 and one with “used” donor structure 208. In an embodiment, the donor structure 208 may have one or more paths 304, e.g., on the outside edge(s) of the donor structure 208, to engage with the drive roller and/or collection roller to avoid contact with the donor material of the donor structure 208 and/or provide sufficient contact (e.g., roughness) between the roller and the donor structure 208. Further, one or more tracks 306 corresponding to the paths may extend between the drive roller and the collection roller to facilitate transport of the donor structure 208 and/or provide stability.
When all or the majority of the “fresh” donor structure 208 has been used or from time to time, the “used” donor structure 208 (and if applicable, remaining “fresh” donor structure 208) may be removed and replaced with “fresh” donor structure 208 (e.g., a new roll of “fresh” donor structure 208 or the same donor structure 208 regenerated with new donor material). In an embodiment, the “used” donor structure 208 may be reconditioned to apply donor material thereon so it can be reused. For example, the membrane may be regenerated in-situ by a refreshment module 308 as the membrane is loaded onto the “used” donor structure roll. A refreshment module 308 may be located at a particular position to regenerate the membrane just before the “used” portion of the membrane is rolled on the “used” donor structure roll. Examples of the structure and functionality of the refreshment module 308 are discussed in further detail below. In an embodiment, a single donor structure 208 loop may be provided per optical engine. In an embodiment, the loop has a length of at least 10 times the substrate length to account for 10× deposition.
In an embodiment, referring to
In an embodiment, the donor structure 208 membrane is a unitary loop of material. In an embodiment, the donor structure 208 comprises a plurality of donor structure 208 membranes that may be separated from each other as they move through the circuit track. An advantage of a plurality of donor structure 208 membranes is that refreshment (e.g., replacement and/or regeneration) may be separately performed on one of the plurality of donor structure 208 membranes without at all or at least insubstantially affecting another of the plurality of donor structure 208 membranes being used for deposition.
In an embodiment, the donor material may comprise a solvent. In which case, the substrate 114 may be heated by a heater 330 to a temperature that almost instantly or very quickly would cause the solvent to evaporate, e.g., about 250 degrees Celsius or more. Therefore, upon contact of the donor material on the substrate, the solvent evaporates leaving the patterning donor material remaining on the substrate. A shield 331 having one or more apertures to allow the donor material to pass to the substrate may be provided to shield the donor structure 208 from the heat of the substrate 114 and/or to shield the donor structure 208 from evaporating solvent.
In an embodiment, when a donor structure 208 membrane has been used, the donor structure 208 membrane may be removed and another “new” membrane inserted. For example, a unitary donor structure 208 membrane loop may be replaced or one of the plurality of donor structure 208 membranes may be replaced. In an embodiment, such transition may occur with no or little stoppage time by, for example, transitioning a “new” membrane into the usage path as the “old” membrane is or becomes finished. Additionally or alternatively, the donor structure 208 membrane may be replaced with every new substrate to be patterned or every certain number of substrates to be patterned in order to take advantage of the time needed to change substrates. The “used” donor structure 208 membrane may be reconditioned to apply donor material thereon so it can be reused.
Additionally or alternatively, the donor structure 208 membrane may be regenerated in-situ as the membrane is circulated in the apparatus. For example, a “used” portion of a unitary donor structure 208 membrane loop may be regenerated as another portion of the unitary donor structure 208 membrane loop is used for deposition. Or, for example, a “used” one of the plurality of donor structure 208 membranes may be regenerated as another of the plurality of donor structure 208 membranes is used for deposition. A refreshment module 308 may be located at a particular position to regenerate the membrane after the “used” part of the membrane is moved from the deposition area between the lens array 170 and the substrate 114 and before it is returned to the deposition area. The refreshment module 308 may comprise separate compartments 312, 314 to perform stripping and regeneration. For example, a first compartment 312 may perform stripping and a second compartment 314 may perform regeneration. In an embodiment, the first and second compartments may be open to allow the donor structure 208 to pass therethrough. In an embodiment, the first and/or second compartments have a seal structure 316 to keep the interior of the compartment substantially separated from the environment exterior to the compartments or module. In an embodiment, the seal structure 316 may comprise a mechanical seal such as one or more brushes, a rubberized surface, etc. In an embodiment, the seal structure may comprise a gas removal outlet to substantially prevent gas or other materials from ingressing and/or egressing interior of the compartment. In an embodiment, the seal structure may further comprise a gas supply inlet to supply a gas to an area adjacent entrance of the donor structure 208 into the compartment or the exit of the donor structure 208 from the compartment. In an embodiment, the seal structure may comprise a gas supply inlet with gas removal outlets immediately adjacent on either side.
In an embodiment, a single donor structure 208 circuit (having a single or a plurality of membranes) may be provided per optical engine. In an embodiment, a single unitary donor structure 208 membrane loop may be provided per optical engine. In an embodiment, a donor structure 208 membrane in the form of a loop has a length of at least 10 times the substrate length to account for 10× deposition.
More generally, the apparatus may have a conveyor system to transport “fresh” donor structure 208 to the deposition area and then transport “used” donor structure 208 to a regeneration module 308. The regenerated donor structure 208 is then transported to the deposition area. Thus, in a variant, the apparatus may comprise, for example, a conveyor system (e.g., a conveyor belt and/or a driver with a track) to move a single donor structure 208 or a plurality of donor structures 208 to the deposition area from a first side of the deposition area and then from the deposition area to a regeneration module 308 on a second side of the deposition area. The conveyor system may then reverse direction to transport the regenerated donor structure(s) 208 to the deposition area and then from the deposition area to the first side where a further regeneration module 308 may be located or the conveyor system may transport the “used” donor structure(s) 208 back to the regeneration module 308 at the second side. Thus, this embodiment may be similar to the roller embodiment of
In an embodiment, referring to
In an embodiment, the rotatable donor structure 208 is a unitary disc or plate of material. In an embodiment, the rotatable donor structure 208 comprises a plurality of donor structure 208 parts that may be separated from each other as they are rotated. An advantage of a plurality of donor structure 208 parts is that refreshment (e.g., replacement and/or regeneration) may be separately performed on one of the plurality of donor structure 208 parts without at all or at least insubstantially affecting another of the plurality of donor structure 208 parts being used for deposition.
In an embodiment, when the rotatable donor structure 208 has been used, the donor structure 208 may be removed and another “new” donor structure 208 inserted. For example, the donor structure 208 may be replaced with every new substrate to be patterned or every certain number of substrates to be patterned in order to take advantage of the time needed to change substrates. The “used” donor structure 208 may be reconditioned to apply donor material thereon so it can be reused.
Additionally or alternatively, the “used” rotatable donor structure 208 (whether unitary disc or plate or a plurality of donor structure 208 parts) may be regenerated in-situ as the donor structure 208 is rotated in the apparatus. A refreshment module 308 may be located at a particular position to regenerate the donor structure 208 after the “used” portion of the donor structure 208 is moved from the deposition area between the lens array 170 and the substrate 114 and before it is returned to the deposition area.
As mentioned above, in an embodiment, the donor structure 208 may be regenerated in-situ in the apparatus. For example, referring to
In an embodiment, the refreshment of the donor structure 208, and thus the refreshment module 308, may include stripping and/or regeneration of the donor material of the donor structure 208. The refreshment of the donor structure 208 may involve stripping the donor material completely from the donor structure 208 and applying a new layer of donor material (which new layer may be recycled donor material stripped from the donor structure 208). Alternatively, the refreshment may involve “repairing” the holes in the donor material on the donor structure 208 by, e.g., adding material directly to the holes, reflowing the material to fill the holes, etc. Regeneration of the donor material of the donor structure 208 may be accomplished in several example ways discussed further herein. The techniques described in relation to stripping and deposit of a new layer may be applied to “repairing” holes, or vice versa, as appropriate. Further, the various techniques discussed in relation to regeneration and stripping may be used to form a donor structure 208 in the first place. For example, the apparatus may be provided a part of the donor structure 208 without donor material and the apparatus applies the donor material (from a store of the donor material in or connected to the apparatus) to the part in the first place (and optionally again to regenerate the donor structure 208). Additionally, for example, the part of the donor structure 208 may be stripped of a coating thereon before application of the donor material.
In an embodiment, stripping the donor structure 208 can take any number of forms. For example, stripping may involve heating the donor structure 208 to a certain temperature to melt off the donor material. Additionally or alternatively, a chemical or plasma may be applied to chemically or mechanically remove the donor material 208. In an embodiment, a solvent is used to remove the donor material from the donor structure 208 and may be the same solvent used to apply the donor material on the donor structure 208 as discussed below. A brush, blade, gas stream, etc. can be used to assist removal of the donor material from the donor structure 208. In an embodiment, the refreshment module may comprise a single compartment that can perform both stripping and regeneration. Alternatively, referring to
In an embodiment, regeneration of the donor material of the donor structure 208 may be accomplished by smoothing or applying a paste or liquid on the donor structure 208. The paste or liquid fills the holes that are generated during the laser induced transfer or forms a new layer on a stripped donor structure 208. The paste or liquid may be mechanically spread over the donor structure 208 by, for example, a doctor blade. In an embodiment, the paste or liquid comprises a solvent which evaporates to leave a substantially solid layer. In an embodiment, the donor structure 208 may be rotated and liquid provided near the rotational axis to allow it to flow outwards over the donor structure 208. In an embodiment, the liquid may be applied in this manner to the rotatable donor structure 208 depicted and described with respect to
In an embodiment, regeneration of the donor material of the donor structure 208 may be accomplished by passing the donor structure 208 into or through a vessel of a refreshment module 308 and depositing a layer of donor material on the donor structure 208. The donor material in the vessel fills the holes that are generated during the laser induced transfer or forms a new layer on a stripped donor structure 208. In an embodiment, the vessel comprises a liquid material, e.g., melted donor material, and the liquid material is brought in contact with (e.g., immerses on at least one side) the “used” donor structure 208. A finite, self limiting layer of donor material should be deposited on the donor structure 208 due to, for example, surface tension. In an embodiment, the regeneration using the vessel may involve electroplating or electrolytic deposition of the donor material on the donor structure 208. In an embodiment, the liquid material may comprise a mixture of a donor material and a solvent. After application of the mixture to the donor structure 208, the solvent evaporates to leave the donor material remaining on the donor structure 208. In an embodiment, the liquid may comprise copper sulfate (CuSO4).
In an embodiment, the vessel of the refreshment module may have a gas comprising the donor material and the donor structure 208 comes in contact with (e.g., is immersed on at least one side) the gas in the vessel in order for a layer of donor material to be applied thereto. In an embodiment, the vessel may produce or provide a plasma to the donor structure 208 in order to deposit donor material thereon. In an embodiment, the refreshment module may use chemical vapor deposition and/or sputtering to apply the donor material to the donor structure 208.
Where the vessel has a liquid or gas, the vessel may be substantially closed to an external environment around the refreshment module. An appropriate seal 316, as discussed above, may be used to facilitate such closure. In an embodiment, the vessel is of large size so as to reduce variation in composition of the liquid and/or gas in the vessel. For example, the vessel may have a volume of greater than or equal to 1 liter, greater than or equal to 2 liters, greater than or equal to 3 liters, greater than or equal to 5 liters. In an embodiment, the vessel has a volume of less than or equal to 100 liters, less than or equal to 70 liters, less than or equal to 50 liters, less than or equal to 25 liters, or less than or equal to 10 liters.
In an embodiment referring to
In a related embodiment, regeneration of the donor material of the donor structure 208 may be accomplished by selectively providing donor material to a donor structure 208 to form a patterned donor material layer 204 exactly or approximately corresponding to the exposure pattern to be applied to the donor structure 208 to form the deposited pattern of donor material on the substrate 114. Thus, the donor material layer 204 does not blanket the donor structure 208 but rather only covers a portion of the donor structure 208 corresponding to the areas where the beam will impinge. In an embodiment, such a patterned donor material layer 204 may be provided upon initial use of the donor structure 208 and/or provided subsequently (e.g., following exposure of a donor structure with a blanket donor material layer 204). An advantage of a patterned donor material layer 204 is potential lower usage of donor material and/or potential increased speed to regenerate.
For example, similar to as discussed above, the regeneration module may have an inkjet (or other) apparatus 318 to selectively apply donor material to the donor structure 208 to form the appropriate patterned donor material layer 204. In an embodiment, the selectively applied donor material (e.g., droplets) may have a lower resolution than the needed donor material for deposition such that the patterned donor material layer 204 is only an approximation corresponding to the exposure pattern to be applied to the donor structure 208 to form the deposited pattern of donor material on the substrate 114. In an embodiment, the regeneration module may “fix” a previously patterned donor material layer 204 by filling holes in such a patterned donor material layer 204. In an embodiment, the donor structure 208 may be stripped of any remaining donor material following an exposure and a new patterned donor material layer 204 is applied.
In an embodiment, regeneration of the donor material of the donor structure 208 may be accomplished by reflow of the donor material layer 204 to fill holes and optionally involve deposition of extra material to compensate for material transferred from the donor material layer 204 during exposure. Where extra material is added, such extra material may be generally added to the donor material layer 204 or may be targeted to the areas needing extra material. For example, as similarly discussed above, an inkjet (or other) apparatus 318 may selectively apply extra donor material to the locations of one or more of the holes in the donor material layer 204. In an embodiment, the selectively applied extra donor material (e.g., droplets) may have a lower resolution than the one or more holes in the donor material layer 204 and the reflow helps to smooth and fill the holes using the selectively applied extra donor material.
For example, regeneration by reflow of the donor material of the donor structure 208 may be accomplished by thermal reflow of the donor material layer 204 to fill holes and optionally involve deposition of extra material to compensate for material transferred from the donor material layer 204 during exposure. The donor structure 208 and/or the donor material layer 204 may be heated using a heater 322 resulting in smoothing of the layer: the holes are filled. Further donor material may be deposited to generate the desired thickness of the donor material layer 204 should the donor material layer 204 not be thick enough after reflow.
In an embodiment, regeneration of the donor material of the donor structure 208 may be accomplished by selective growth of a part of the donor structure 208 followed by reflow of the donor material layer 204 and optionally deposition of extra donor material. This method may be used in a situation where, for example, the donor material layer 204 overlies a release or other layer (e.g., transparent material 202). Thus, the release or other layer may be regenerated followed by regeneration of the donor material layer 204. For example, the release or other layer may have deposited thereon a chemically specific deposition material that results in repair of the release or other layer. The donor material layer 204 may be reflowed as discussed above and optionally extra material deposited thereon. In an embodiment, the donor material layer 204 may be regenerated using any of the other methods disclosed herein or elsewhere.
In an embodiment, the donor structure 208 may be an aluminum foil. If the aluminum foil has a layer thereon, e.g., a non-metal layer, the beam may evaporate such a layer thus leaving a hole all the way through the donor structure 208. In an embodiment, if the aluminum foil has a layer thereon, e.g., a non-metal layer, the beam may not evaporate such a layer, leaving a hole only in the donor material. The donor structure 208, e.g., the unused part of the donor structure 208, may be refreshed as described herein. For example, it may be discarded, be melted to form a new donor structure, be regenerated by jetting on regenerating donor material at locations where new donor material is needed with a bit lower resolution compared to the pattern to be formed on the substrate, etc.
In an embodiment, as discussed above, the donor structure 208 may comprise a holder material 202 on to which a donor material layer 204 is electrostatically or electromagnetically clamped. In an embodiment, donor material layer 204 electrostatically or electromagnetically clamped to the holder material 202 comprises a powder or particles of material, such as metal powder or particles. Regeneration of such a donor structure 208 (after it has material 204 deposited therefrom to the substrate 114) may be accomplished by stripping off the donor material layer 204 by, for example, reversing or disengaging the charge or polarity of the donor structure 208. As a result, the remaining donor material 204 may fall off or be physically removed therefrom (by, for example, a brush, a gas stream or other mechanism). A new donor material layer 204 may be applied to the holder material 202 by subsequently reversing or engaging the charge or polarity of the donor structure 208. A particular charge or polarity can actively be provided to the holder material 202 and/or to the donor material 204 to facilitate the electrostatic or electromagnetic clamping. For example, a refreshment module 308 may have an appropriate electrical and/or magnetic structure to facilitate the relevant charging or polarity of the holder material 202 and/or the donor material 204. In an embodiment, the donor structure 208 may be connected to a source of charge or magnetism during use in the deposition area and/or other areas of the apparatus to facilitate maintaining the donor material layer 204 on the holder material 202.
Additionally or alternatively, as discussed above, the beam can be used to ablate a material of the substrate 114. In particular, the beam can be used to introduce a phase transfer. Controller 218 may be configured to configure the radiation source to provide a beam of increased power compared to that used for material deposition and/or photolithography.
Additionally or alternatively, similar to a photolithography resist process, the beam can be used to cause a local change in a property of a material on the substrate 114 followed by removal of material that has not been changed. For example, the substrate 114 may be covered with a material that solidifies or changes its state on exposure to the radiation of the beam. As an example, the substrate 114 may be covered with a powder, such as a metal powder (adhered, for example, electrostatically or electromagnetically as discussed above). The beam may then cause a localized portion of the powder to change to a liquid state such that it congeals with adjacent powder and then turns into a gel or solid. For example, the material on the substrate may sinter. The remaining unchanged powder stays in powder form and may then be removed (e.g., by reversing or disengaging the charge or polarity of the substrate 114 having the powder) to leave a pattern formed from the exposed powder. Other processing steps may be used to convert the exposed powder into a solid form corresponding to the pattern, such as cooling, further exposure to radiation, etc.
In a related process, referring to
In an embodiment, referring to
In an embodiment, referring to
In an embodiment, the patterned material 202 comprises a base layer of high surface tension material 332 (e.g., quartz) and an overlying low surface tension material layer 334. Through, e.g., a photoresist exposure and etching process, one or more apertures may be formed in the low surface tension material layer to reveal the high surface tension material. In an embodiment, a high surface tension material may be treated to form the low surface tension area. Other processes may be used to form the interspersed arrangement of one or more high surface tension areas and one or more low surface tension areas. In addition to or as an alternative to a reticle based photolithography technique to form the patterned material 202, contact lithography, foil mask lithography, imprint lithography or maskless lithography can be used to create the mask used to etch low surface tension material away.
In an embodiment, the high surface tension area 332 comprises quartz, sapphire (Al2O3) and/or YAG (yttrium aluminum garnet, Y3Al5O12). In an embodiment, the high surface tension area 332 may comprise a transparent oxide. In an embodiment, the low surface tension area 334 may comprise an organic (e.g., polytetrafluoroethylene, or a fluorinated self assembled monolayer (SAM)) or inorganic (e.g., boron nitride) material. In an embodiment, the low surface tension area 334 may comprise a polymer, e.g., a fluorinated polymer or polydimethylsiloxane. Examples of molecules are (1H,1H,2H,2H-Perfluorooctyl)Trichlorosilane and/or (alkyl)Trichlorosilane (with alkyl chains longer than C6 (hexyl and longer). In the case of, e.g., polytetrafluoroethylene and/or boron nitride, the layer may be substantially thicker than one monolayer (e.g., couple of nanometers) which can help in containing the to be ablated donor material 204.
Referring to
A LIFT process using a continuous sheet of donor material may cause debris in the form of small particles during the donor material transfer process. Thus, an advantage of this patterned material 202 arrangement is that the donor material 204 is not continuous and therefore may be less prone to debris formation during the donor material transfer process. For example, since there would be no material adjacent an “island”, a beam 200 that extends beyond the size of the “island” but before impacting another “island” would cause material transfer only from the “island”. Further, an “island” can cause discrete material transfer compared to a continuous layer since in a continuous layer a portion is “torn” from the layer, thus potentially causing adjacent material to be dislodged as particles.
In an embodiment, referring to
Referring to
Referring to
Referring to
In an embodiment, 400 individually addressable elements 102 may be provided. In an embodiment, 600-1200 working individually addressable elements 102 may be provided with, optionally, additional individually addressable elements 102 as, for example, a reserve and/or for correction exposures (as, for example, discussed above). The number of working individually addressable elements 102 may depend, for example, on the resist, which requires a certain dosage of radiation for patterning.
Where the individually addressable elements are the diodes, they may be operated in the steep part of the optical output power vs. forward current curve (240 mA v. 35 mA) as shown, e.g., in
The number of individually addressable elements 102 may depend, inter alia (and as to an extent also noted above), on the length of the exposure region that the individually addressable elements 102 are intended to cover, the speed with which the individually addressable elements 102 is moved, if any, during exposure, the speed and amount of deflection by a deflector, the spot size (i.e., cross-sectional dimension, e.g., width/diameter, of the spot projected on the substrate from an individually addressable element 102), the desired intensity each of the individually addressable elements should provide (e.g. whether it is desired to spread the intended dose for a spot on the substrate over more than one individually addressable element to avoid damage to the substrate or resist on the substrate), the desired scan speed of the substrate, cost considerations, the frequency with which the individually addressable elements can be turned “on” or “off”, and the desire for redundant individually addressable elements 102 (as discussed earlier; e.g. for correction exposures or as a reserve, for instance if one or more individually addressable elements break down). In an embodiment, there are for an optical column at least 100 individually addressable elements 102, for instance at least 200 individually addressable elements, at least 400 individually addressable elements, at least 600 individually addressable elements, at least 1000 individually addressable elements, at least 1500 individually addressable elements, at least 2500 individually addressable elements, or at least 5000 individually addressable elements. In an embodiment, there are for an optical column less than 50000 individually addressable elements 102, for instance less than 25000 individually addressable elements, less than 15000 individually addressable elements, less than 10000 individually addressable elements, less than 7500 individually addressable elements, less than 5000 individually addressable elements, less than 2500 individually addressable elements, less than 1200 individually addressable elements, less than 600 individually addressable elements, or less than 300 individually addressable elements.
In an embodiment, an optical column comprises for each 10 cm of length of exposure region (i.e., normalizing the number of individually addressable elements in the optical column to 10 cm of length of exposure region) at least 100 individually addressable elements 102, for instance at least 200 individually addressable elements, at least 400 individually addressable elements, at least 600 individually addressable elements, at least 1000 individually addressable elements, at least 1500 individually addressable elements, at least 2500 individually addressable elements, or at least 5000 individually addressable elements. In an embodiment, an optical column comprises for each 10 cm of length of exposure region (i.e., normalizing the number of individually addressable elements in the optical column to 10 cm of length of exposure region) less than 50000 individually addressable elements 102, for instance less than 25000 individually addressable elements, less than 15000 individually addressable elements, less than 10000 individually addressable elements, less than 7500 individually addressable elements, less than 5000 individually addressable elements, less than 2500 individually addressable elements, less than 1200 individually addressable elements, less than 600 individually addressable elements, or less than 300 individually addressable elements.
In an embodiment, an optical column comprises less than 75% redundant individually addressable elements 102, e.g. 67% or less, 50% or less, about 33% or less, 25% or less, 20% or less, 10% or less, or 5% or less. In an embodiment an optical column comprises at least 5% redundant individually addressable elements 102, e.g. at least 10%, at least 25%, at least 33%, at least 50%, or at least 65%. In an embodiment, the optical column comprises about 67% redundant individually addressable elements.
In an embodiment, spot size of an individual addressable element on the substrate is 10 microns or less, 5 microns or less, e.g. 3 microns or less, 2 microns or less, 1 micron or less, 0.5 micron or less, 0.3 micron or less, or about 0.1 micron. In an embodiment, spot size of an individual addressable element on the substrate is 0.1 micron or more, 0.2 micron or more, 0.3 micron or more, 0.5 micron or more, 0.7 micron or more, 1 micron or more, 1.5 microns or more, 2 microns or more, or 5 microns or more. In an embodiment, spot size is about 0.1 micron. In an embodiment, spot size is about 0.5 micron. In an embodiment, spot size is about 1 micron.
It can be seen that the array of radiation spots S is arranged at an angle α relative to the substrate scanning direction (the edges of the substrate 114 lie parallel to the X- and Y-directions). This is done so that, when the substrate 114 is moved in the scanning direction (the X-direction), each radiation spot will pass over a different area of the substrate, thereby allowing the entire substrate to be covered by the array of radiation spots S. In an embodiment, the angle α is at most 20°, 10°, for instance at most 5°, at most 3°, at most 1°, at most 0.5°, at most 0.25°, at most 0.10°, at most 0.05°, or at most 0.01°. In an embodiment, the angle α is at least 0.0001°, e.g. at least 0.001°. The angle of inclination α and the width of the array in the scanning direction are determined in accordance with the image spot size and array spacing in the direction perpendicular to the scanning direction to ensure the whole surface area of the substrate 114 is addressed.
In the embodiments described herein, a controller is provided to control the individually addressable elements 102 and/or patterning device 104. For example, in an example where the individually addressable elements are radiation emitting devices, the controller may control when the individually addressable elements are turned ON or OFF and enable high frequency modulation of the individually addressable elements. The controller may control the power of the radiation emitted by one or more of the individually addressable elements. The controller may modulate the intensity of radiation emitted by one or more of the individually addressable elements. The controller may control/adjust intensity uniformity across all or part of an array of individually addressable elements. The controller may adjust the radiation output of the individually addressable elements to correct for imaging errors, e.g., etendue and optical aberrations (e.g., coma, astigmatism, etc.). Similar control may be provided by a deflector 112 of the patterning device 104.
In photolithography, a desired feature may be created on a substrate by selectively exposing a layer of resist on a substrate to radiation, e.g. by exposing the layer of resist to patterned radiation. Areas of the resist receiving a certain minimum radiation dose (“dose threshold”) undergo a chemical reaction, whereas other areas remain unchanged. The thus created chemical differences in the resist layer allow for developing the resist, i.e. selectively removing either the areas having received at least the minimum dose or removing the areas that did not receive the minimum dose. As a result, part of the substrate is still protected by a resist whereas the areas of the substrate from which resist is removed are exposed, allowing e.g. for additional processing steps, for instance selective etching of the substrate, selective metal deposition, etc. thereby creating the desired feature. Patterning the radiation may be effected by controlling the patterning device 104 such that the radiation that is transmitted to an area of the resist layer on the substrate within the desired feature is at a sufficiently high intensity that the area receives a dose of radiation above the dose threshold during the exposure, whereas other areas on the substrate receive a radiation dose below the dose threshold by providing a zero or significantly lower radiation intensity.
In practice, the radiation dose at the edges of the desired feature may not abruptly change from a given maximum dose to zero dose even if set to provide the maximum radiation intensity on one side of the feature boundary and the minimum radiation intensity on the other side. Instead, due to diffractive effects, the level of the radiation dose may drop off across a transition zone. The position of the boundary of the desired feature ultimately formed after developing the resist is then determined by the position at which the received dose drops below the radiation dose threshold. The profile of the drop-off of radiation dose across the transition zone, and hence the precise position of the feature boundary, can be controlled more precisely by providing radiation to points on the substrate that are on or near the feature boundary not only to maximum or minimum intensity levels but also to intensity levels between the maximum and minimum intensity levels. This is commonly referred to as “grayscaling” or “grayleveling”.
Grayscaling may provide greater control of the position of the feature boundaries than is possible in a lithography system in which the radiation intensity provided to the substrate can only be set to two values (namely just a maximum value and a minimum value). In an embodiment, at least three different radiation intensity values can be projected, e.g. at least 4 radiation intensity values, at least 8 radiation intensity values, at least 16 radiation intensity values, at least 32 radiation intensity values, at least 64 radiation intensity values, at least 100 radiation intensity values, at least 128 radiation intensity values, or at least 256 radiation intensity values. If the patterning device is a radiation source itself (e.g. an array of light emitting diodes or laser diodes), grayscaling may be effected, e.g., by controlling the intensity levels of the radiation being transmitted. If the patterning device include a deflector 112, grayscaling may be effected, e.g., by controlling the tilting angles of the deflector 112. Also, grayscaling may be effected by grouping a plurality of programmable elements and/or deflectors and controlling the number of elements and/or deflectors within the group that are switched on or off at a given time.
In one example, the patterning device may have a series of states including: (a) a black state in which radiation provided is a minimum, or even a zero contribution to the intensity distribution of its corresponding pixel; (b) a whitest state in which the radiation provided makes a maximum contribution; and (c) a plurality of states in between in which the radiation provided makes intermediate contributions. The states are divided into a normal set, used for normal beam patterning/printing, and a compensation set, used for compensating for the effects of defective elements. The normal set comprises the black state and a first group of the intermediate states. This first group will be described as gray states, and they are selectable to provide progressively increasing contributions to corresponding pixel intensity from the minimum black value up to a certain normal maximum. The compensation set comprises the remaining, second group of intermediate states together with the whitest state. This second group of intermediate states will be described as white states, and they are selectable to provide contributions greater than the normal maximum, progressively increasing up to the true maximum corresponding to the whitest state. Although the second group of intermediate states is described as white states, it will be appreciated that this is simply to facilitate the distinction between the normal and compensatory exposure steps. The entire plurality of states could alternatively be described as a sequence of gray states, between black and white, selectable to enable grayscale printing.
It should be appreciated that grayscaling may be used for additional or alternative purposes to that described above. For example, the processing of the substrate after the exposure may be tuned such that there are more than two potential responses of regions of the substrate, dependent on received radiation dose level. For example, a portion of the substrate receiving a radiation dose below a first threshold responds in a first manner; a portion of the substrate receiving a radiation dose above the first threshold but below a second threshold responds in a second manner; and a portion of the substrate receiving a radiation dose above the second threshold responds in a third manner. Accordingly, grayscaling may be used to provide a radiation dose profile across the substrate having more than two desired dose levels. In an embodiment, the radiation dose profile has at least 2 desired dose levels, e.g. at least 3 desired radiation dose levels, at least 4 desired radiation dose levels, at least 6 desired radiation dose levels or at least 8 desired radiation dose levels.
It should further be appreciated that the radiation dose profile may be controlled by methods other than by merely controlling the intensity of the radiation received at each point, as described above. For example, the radiation dose received by each point may alternatively or additionally be controlled by controlling the duration of the exposure of said point. As a further example, each point may potentially receive radiation in a plurality of successive exposures. The radiation dose received by each point may, therefore, be alternatively or additionally controlled by exposing said point using a selected subset of said plurality of successive exposures.
Further, while the discussion above regarding gray scaling focused on photolithography, similar concepts may be applied to the material removal and material deposition discussed herein. For example, ablation may be controlled with different dose levels to provide gray scaling. Similarly, dose levels may be controlled to provide gray scaling associated with the material deposition.
In order to form the pattern on the substrate, it is necessary to set the patterning device to the requisite state at each stage during the exposure process. Therefore control signals, representing the requisite states, must be transmitted to the patterning device. Desirably, the lithographic apparatus includes a controller that generates the control signals. The pattern to be formed on the substrate may be provided to the lithographic apparatus in a vector-defined format e.g., GDSII. In order to convert the design information into the control signals, the controller includes one or more data manipulation devices, each configured to perform a processing step on a data stream that represents the pattern. The data manipulation devices may collectively be referred to as the “datapath”.
The data manipulation devices of the datapath may be configured to perform one or more of the following functions: converting vector-based design information into bitmap pattern data; converting bitmap pattern data into a required radiation dose map (namely a required radiation dose profile across the substrate); converting a required radiation dose map into required radiation intensity values for each individually controllable element; and converting the required radiation intensity values for each individually controllable element into corresponding control signals.
In an embodiment, the control signals may be supplied to the individually controllable elements 102 and/or one or more other devices (e.g., a deflector and/or sensor) by wired or wireless communication. Further, signals from the individually controllable elements 102 and/or from one or more other devices (e.g., a deflector and/or sensor) may be communicated to the controller. In a similar manner to the control signals, power may be supplied to the individually controllable elements 102 or one or more other devices (e.g., a deflector and/or sensor) by wired or wireless means. For example, in a wired embodiment, power may be supplied by one or more lines, whether the same as the ones that carry the signals or different. A sliding contact arrangement may be provided to transmit power. In a wireless embodiment, power may be delivered by RF coupling.
While the previous discussion focused on the control signals supplied to the individually controllable elements 102 and/or one or more other devices (e.g., a deflector and/or a sensor), they should be understood to encompass in addition or alternatively, through appropriate configuration, transmission of signals from the individually controllable elements 102 and/or from one or more other devices (e.g., a deflector and/or sensor) to the controller. So, communication may be one-way (e.g., only to or from the individually controllable elements 102 and/or one or more other devices (e.g., a deflector and/or sensor)) or two-way (i.e., from and to the individually controllable elements 102 and/or one or more other devices (e.g., a deflector and/or sensor)).
In an embodiment, the control signals to provide the pattern may be altered to account for factors that may influence the proper supply and/or realization of the pattern on the substrate. For example, a correction may be applied to the control signals to account for the heating of one or more of the individually controllable elements 102, lenses, etc. Such heating may cause changed pointing direction of the individually controllable elements 102, lenses, etc., change in uniformity of the radiation, etc. In an embodiment, a measured temperature and/or expansion/contraction associated with an individually controllable elements 102 and/or other element from, e.g., a sensor may used to alter the control signals that would have been otherwise provided to form the pattern. So, for example, during exposure, the temperature of the individually controllable elements 102 may vary, the variance causing a change of the projected pattern that would be provided at a single constant temperature. Accordingly, the control signals may be altered to account for such variance. Similarly, in an embodiment, results from the alignment sensor and/or the level sensor 150 may be used to alter the pattern provided by the individually controllable elements 102. The pattern may be altered to correct, for example, distortion, which may arise from, e.g., optics (if any) between the individually controllable elements 102 and the substrate 114, irregularities in the positioning of the substrate 114, unevenness of the substrate 114, etc.
In an embodiment, the change in the control signals may be determined based on theory of the physical/optical results on the desired pattern arising from the measured parameter (e.g., measured temperature, measured distance by a level sensor, etc.). In an embodiment, the change in the control signals may be determined based on an experimental or empirical model of the physical/optical results on the desired pattern arising from the measured parameter. In an embodiment, the change of the control signals may be applied in a feedforward and/or feedback manner.
In an embodiment, the lithographic apparatus may comprise a sensor 118 to measure a characteristic of the radiation that is or to be transmitted toward the substrate by one or more individually controllable elements 102. Such a sensor may be a spot sensor or a transmission image sensor. The sensor may be used to, for example, determine the intensity of radiation from an individually controllable element 102, uniformity of radiation from an individually controllable element 102, a cross-sectional size or area of the spot of radiation from an individually controllable element 102, and/or the location (in the X-Y plane) of the spot of radiation from an individually controllable element 102.
In an embodiment, the sensor 118 may be provided on the frame 160 and receives radiation from an individually controllable element 102 via a beam redirecting structure (e.g., a reflective mirror arrangement) in the beam path of an individually controllable element 102. For example, the individually controllable element(s) 102 move in the X-Y plane and so the individually controllable element(s) 102 can be located to provide radiation to the beam redirecting structure. In an embodiment, the sensor 118 may be provided on the frame 160 and receives radiation from an individually controllable element 102 from the back side of the individually controllable element 102, i.e., the side opposite from which the exposure radiation is provided. Similarly, the individually controllable element(s) 102 move in the X-Y plane and so the individually controllable element(s) 102 can be located to provide radiation to the sensor 118. In an embodiment, the sensor 118 on the frame 160 is in a fixed position or else may be movable by virtue of, e.g., an associated actuator. The sensor 118 on the frame 160 may be used to provide “on-the-fly” sensing in addition to or alternatively to pre- and/or post-exposure sensing. In an embodiment, a sensor 118 is movable by an actuator and may be located under the path of where the substrate table would move (as shown in
In operation to measure a characteristic of the radiation that is or to be transmitted toward the substrate by one or more individually controllable elements 102, the sensor 118 is located in a path of radiation from an individually controllable element 102, by moving the sensor 118 and/or moving the radiation beam of the individually controllable element 102. So, as an example, the substrate table 106 may be moved to position sensor 118 in a path of radiation from an individually controllable element 102. In this case, the sensor 118 is positioned into a path of an individually controllable element 102 at the exposure region 234. In an embodiment, the sensor 118 may be positioned into a path of an individually controllable element 102 outside of the exposure region 234. Once located in the path of radiation, the sensor 118 can detect the radiation and measure a characteristic of the radiation. To facilitate sensing, the sensor 118 may move with respect to the individually controllable element 102 and/or the individually controllable element 102 (and/or the beam) may be moved with respect to the sensor 118.
As a further example, an individually controllable element 102 may be moved to a position so that radiation from the individually controllable element 102 impinges on a beam redirecting structure. The beam redirecting structure directs the beam to a sensor 118 on the frame 160. To facilitate sensing, the sensor 118 may move with respect to the individually controllable element 102 and/or the individually controllable element 102 (and/or beam) may be moved with respect to the sensor 118.
In an embodiment, the sensor 118 may be fixed or moving. If fixed, an individually controllable element 102 and/or beam is desirably movable with respect to the fixed sensor 118 to facilitate sensing. For example, an individually controllable element 102 may be moved (e.g., rotated or translated) with respect to the sensor 118 (e.g., a sensor 118 on the frame 160) to facilitate sensing by the sensor 118. If the sensor 118 is movable (e.g., the sensor 118 on the substrate table 106), an individually controllable element 102 and/or the beam may be kept still for the sensing, or else moved to, for example, speed up sensing.
The sensor 118 may be used to calibrate the patterning device 104, such as the deflector 112 and/or one or more of the individually controllable elements 102. For example, the location of the spot from the patterning device can be detected by the sensor 118 prior to exposure and the system accordingly calibrated. The exposure can then be regulated based on this expected location of the spot (e.g., the position of the substrate 114 is controlled, the position of the individually controllable element 102 and/or beam is controlled, the turning OFF or ON of an individually controllable element 102 is controlled, etc.). Further, calibrations may take place subsequently. For example, a calibration may take place immediately after exposure before a further exposure using, for example, a sensor 118 on the trailing edge of the substrate table 106. Calibration may take place before each exposure, after a certain number of exposures, etc. Further, the location of a spot may be detected “on-the-fly” using a sensor 118 and the exposure is accordingly regulated. The patterning device 104, such as the deflector 112 and/or the individually controllable element 102, may perhaps be recalibrated based on the “on-the-fly” sensing.
In an embodiment, a position sensor may be provided to determine the position of one or more of the individually controllable elements 102, the deflector 112, a lens, etc. in up to 6 degrees of freedom. In an embodiment, the sensor may comprise an interferometer. In an embodiment, the sensor may comprise an encoder which may be used to detect one or more single dimension encoder gratings and/or one or more two dimensional encoder gratings.
In an embodiment, a sensor may be provided to determine a characteristic of the radiation that has been transmitted to the substrate. In this embodiment, a sensor captures radiation redirected by the substrate. In an example use, the redirected radiation captured by sensor may be used to facilitate determining the location of the spot of radiation from an individually controllable element 102 (e.g., misalignment of the spot of radiation from an individually controllable element 102). In particular, the sensor may capture radiation redirected from a just exposed portion of the substrate, i.e., a latent image. A measurement of the intensity of this tail redirected radiation may give an indication of whether the spot was properly aligned. For example, the repeated measurement of this tail may give a repetitive signal, a deviation from which would indicate a misalignment of the spot (e.g., an out of phase signal can indicate misalignment). For example, three detection regions may be provided whose results may be compared and/or combined to facilitate recognition of the misalignment. Only one detection region need be used.
In an embodiment, one or more of the individually addressable elements 102 are movable. For example, the one or more of the individually addressable elements 102 may be movable in X-, Y-, and/or Z-directions. In addition or alternatively, the one or more of the individually addressable elements 102 may be rotatable about the X-, Y- and/or Z-directions (i.e., Rx, Ry and/or Rz motion).
In an embodiment, the one or more of the individually addressable elements 102 may be movable between an exposure region wherein the one or more individually addressable elements are used to project all or part of the beam 110, and a location outside of the exposure region wherein the one or more individually addressable elements do not project any of the beam 110. In an embodiment, the one or more individually addressable elements 102 are radiation emitting devices that are turned ON or at least partly ON, i.e., they emit radiation, in the exposure region 234 (the shaded region in FIGS. 40(A)-(C)) and are turned OFF, i.e., they do not emit radiation, when located outside of the exposure region 234.
In an embodiment, the one or more individually addressable elements 102 are radiation emitting devices that may be turned ON in the exposure region 234 and outside of the exposure region 234. In such a circumstance, one or more individually addressable elements 102 may be turned on outside of the exposure region 234 to provide a compensating exposure if, for example, the radiation was not properly projected in the exposure region 234 by one or more individually addressable elements 102.
In an embodiment, the exposure region 234 is an elongate line. In an embodiment, the exposure region 234 is a single dimensional array of one or more individually addressable elements 102. In an embodiment, the exposure region 234 is a two dimensional array of one or more individually addressable elements 102. In an embodiment, the exposure region 234 is elongate.
In an embodiment, each of the movable individually addressable elements 102 may be movable separately and not necessarily together as a unit.
In an embodiment, the one or more individually addressable elements 102 are movable, and in use move, in a direction transverse to a direction of propagation of the beam 110 at least during projection of the beam 110. For example, in an embodiment, the one or more individually addressable elements 102 are radiation emitting devices that move in a direction substantially perpendicular to a direction of propagation of the beam 110 during projection of the beam 110.
In an embodiment, one or more arrays 230 of individually addressable elements 102 are laterally displaceable and/or rotatable plate(s) having a plurality of spatially separated individually addressable elements 102 arranged along the plate(s) as shown in
In an embodiment, each of the arrays 230 is a rotatable plate having a plurality of spatially separated individually addressable elements 102 arranged around the plate. In use, each plate rotates about its own axis 236. The array 230 may alternately rotate in clockwise and anti-clockwise directions. Alternatively, each of the arrays 230 may rotate in a clockwise direction or rotate in an anti-clockwise direction. In an embodiment, the array 230 rotates completely around. In an embodiment, the array 230 rotates an arc less than completely around. In an embodiment, the array 230 may rotate about an axis extending in the X- or Y-direction if, for example, the substrate scans in the Z-direction.
In an embodiment, the rotatable plate may have configuration as shown in
In use, the motion of the individually addressable elements 102 are appropriately timed to be located in the exposure region 234 so as to project all or part of the beam 110. For example, in an embodiment, the one or more individually addressable elements 102 are radiation emitting devices and the turning ON or OFF of the individually addressable elements 102 is timed so that one or more individually addressable elements 102 are turned ON when they are in exposure region 234 and turned OFF when they are outside of region 234. So, in an embodiment, the radiating emitting devices 102 could be all kept on during motion and then certain ones of the radiation emitting devices 102 are modulated off in the exposure region 234. An appropriate shield between the radiation emitting devices 102 and the substrate and outside of the exposure region 234 may be required to shield the exposure region 234 from turned on radiation emitting devices 102 outside of the exposure region 234. Having the radiation emitting devices 102 consistently on can facilitate having the radiation emitting devices 102 at a substantially uniform temperature during use. In an embodiment, the radiation emitting devices 102 could kept off most of the time and one or more of the radiation emitting devices 102 turned on when in the exposure region 234.
In an embodiment, more movable individually addressable elements than theoretically needed (e.g. on a rotatable plate) may be provided. A possible advantage of this arrangement is that if one or more movable individually addressable elements break or fail to operate, one or more other of the movable individually addressable elements can be used instead. In addition or alternatively, extra movable individually addressable elements may have an advantage for controlling thermal load on the individually addressable elements as the more movable individually addressable elements there are, the more opportunity there is for movable individually addressable elements outside of the exposure region 234 to cool off.
In an embodiment, one or more individually addressable elements may comprise a temperature control arrangement. For example, an array 230 may have a fluid (e.g., liquid) conducting channel to transport cooling fluid on, near or through array 230 to cool the array. The channel may be connected to an appropriate heat exchanger and pump to circulate fluid through the channel. A sensor may be provided in, on or near the array, to measure a parameter of the array 230, which measurement may be used to control, e.g., the temperature of the fluid flow provided by the heat exchanger and pump. In an embodiment, sensor may measure the expansion and/or contraction of the array 230 body, which measurement may be used to control the temperature of the fluid flow provided by the heat exchanger and pump. Such expansion and/or contraction may be a proxy for temperature. In an embodiment, the sensor may be integrated with the array 230 and/or may be separate from the array 230. The sensor separate from the array 230 may be an optical sensor.
In an embodiment, an array 230 may have one or more fins to increase the surface area for heat dissipation. The fin(s) may be, for example, on a top surface of the array 230 and/or on a side surface of the array 230. Optionally, one or more further fins may be provided to cooperate with the fin(s) on the array 230 to facilitate heat dissipation. For example, the further fin(s) is able to absorb heat from the fin(s) on the array 230 and may comprise a fluid (e.g., liquid) conducting channel and an associated heat exchanger/pump.
In an embodiment, an array 230 may be located at or near a fluid confinement structure configured to maintain a fluid in contact with the array 230 body to facilitate heat dissipation via the fluid. In an embodiment, the fluid 238 may be a liquid, e.g., water. In an embodiment, the fluid confinement structure provides a seal between it and the array 230 body. In an embodiment, the seal may be a contactless seal provided through, for example, a flow of gas or capillary force. In an embodiment, the fluid is circulated, akin to as discussed with respect to the fluid conducting channel, to promote heat dissipation. The fluid may be supplied by a fluid supply device. In an embodiment, an array 230 may be located at or near a fluid supply device configured to project a fluid toward the array 230 body to facilitate heat dissipation via the fluid. In an embodiment, the fluid is a gas, e.g., clean dry air, N2, an inert gas, etc.
In an embodiment, the array 230 body is a substantially solid structure with, for example, a cavity for the fluid conducting channel. In an embodiment, the array 230 body is a substantially frame like structure that is mostly open and to which are attached the various components, e.g., the individually addressable elements 102, the fluid conducting channel, etc. This open like structure facilitates gas flow and/or increases the surface area. In an embodiment, the array 230 body is a substantially solid structure with a plurality of cavities into or through the body to facilitate gas flow and/or increase the surface area.
While embodiments have been described above to provide cooling, the embodiments alternatively or in addition may provide heating.
In an embodiment, the array 230 is desirably kept at a substantially constant steady state temperature during exposure use. So, for example, all or many of the individually addressable elements 102 of array 230 may be powered on, before exposure, to reach at or near a desired steady state temperature and during exposure, any one or more temperature control arrangements may be used to cool and/or heat the array 230 to maintain the steady state temperature. In an embodiment, any one or more temperature control arrangements may be used to heat the array 230 prior to exposure to reach at or near a desired steady state temperature. Then, during exposure, any one or more temperature control arrangements may be used to cool and/or heat the array 230 to maintain the steady state temperature. A measurement from the sensor described above can be used in a feedforward and/or feedback manner to maintain the steady state temperature. In an embodiment, each of a plurality of arrays 230 may have the same steady state temperature or one or more arrays 230 of a plurality of arrays 230 may have a different steady state temperature than one or more other arrays 230 of a plurality of arrays 230. In an embodiment, the array 230 is heated to a temperature higher than the desired steady state temperature and then falls during exposure because of cooling applied by any one or more temperature control arrangements and/or because the usage of the individually addressable elements 102 isn't sufficient to maintain the temperature higher than the desired steady state temperature.
In an embodiment, the foregoing description of movement, temperature control, etc. of one or more individually addressable elements 102 may be applied to other elements such one or more selected from: lens(es) 122, deflector(s) 112, lens(es) 124, lens(es) 140 and/or lens(es) 170. Further, one or more of the various elements may be movable with respect to one or more of the other elements and/or movable with respect one or more of the same element. For example, the lens(es) 140 and/or lens(es) 170 may be movable with respect to the one or more individually addressable elements 102 and, for example, one or more of lenses 140 and/or lenses 170 may be movable with respect to the one or more of other lenses 140 and/or lenses 170.
In an embodiment, a lens array as described herein is associated or integrated with the individually addressable element(s). For example, an array of lenses 122 may be attached to each of the arrays 230 and thus may be movable (e.g., rotatable) with the individually addressable elements 102. The lens array may be displaceable with respect to the individually addressable elements 102 (e.g., in the Z-direction). In an embodiment, a plurality of lens arrays may be provided for an array 230, each lens array plate being associated with different subset of the plurality of individually addressable elements 102.
In an embodiment, a single separate lens 122 may be attached in front of each individually addressable element 102 and be movable with the individually addressable element 102 (e.g., rotatable). Further, the lens 122 may be displaceable with respect to the individually addressable element 102 (e.g., in the Z-direction) through the use of an actuator. In an embodiment, the individually addressable element 102 and the lens 122 may be displaced together relative to a body of the array 230 by an actuator. In an embodiment, the actuator is configured to only displace lens 122 (i.e., with respect to individually addressable element 102 or together with individually addressable element 102) in the Z-direction. In an embodiment, the actuator is configured to displace lens 122 in up to 3 degrees of freedom (the Z-direction, rotation about the X-direction, and/or rotation about the Y-direction). In an embodiment, the actuator is configured to displace lens 122 in up to 6 degrees of freedom. Where the lens 122 is movable with respect to its individually addressable element 102, the lens 122 may be moved by the actuator to change the position of the focus of the lens 122 with respect to the substrate. Where the lens 122 is movable with its individually addressable element 102, the focus position of the lens 122 is substantially constant but displaced with respect to the substrate. In an embodiment, the movement of lens 122 is individually controlled for each lens 122 associated with each individually addressable element 102 of the array 230. In an embodiment, a subset of a plurality of lenses 122 are movable together with respect to, or together with, their associated subset of the plurality of individually addressable elements 102. In this latter situation, fineness of focus control may be expensed for lower data overhead and/or faster response. In an embodiment, the size of the spot of radiation provided by an individually addressable element 102 may be adjusted by defocus, i.e., the more defocused, the larger the spot size.
In an embodiment, the individually addressable element 102 may be a radiation emitting device e.g., a laser diode. Such radiation emitting device may have high spatial coherence and accordingly may present a speckle problem. To avoid such a speckle problem, the radiation emitted by the radiation emitting device should be scrambled by shifting the phase of a beam portion with respect to another beam portion. In an embodiment, a plate may be located on, for example, frame 160 and there may be relative movement between the individually addressable elements 102 and the plate 250. The plate causes disruption of the spatial coherence of the radiation emitted by the individually addressable elements 102 toward the substrate. In an embodiment, the plate is located between a lens 122 and its associated individually addressable element 102. In an embodiment, the plate may be located between the lens 122 and the substrate.
In an embodiment, a spatial coherence disrupting device may be located between the substrate and at least the individually addressable elements 102. In an embodiment, the spatial coherence disrupting device is located or locatable in a beam path between the individually addressable elements 102 and the substrate. In an embodiment, the spatial coherence disrupting device is a phase modulator, a vibrating plate, or a rotating plate. As an individually addressable element 102 projects radiation toward the substrate, the spatial coherence disrupting device causes disruption of the spatial coherence of the radiation emitted by the individually addressable element 102.
In an embodiment, the lens 122 array (whether together as unit or as individual lenses) is attached to an array 230, desirably via high thermal conductivity material, to facilitate conduction of heat from the lens array to the array 230, where cooling may be more advantageously provided.
In an embodiment, one or more focus or level sensors may be provided. For example, a sensor may be configured to measure focus for each individually addressable element 102 or for a plurality of individually addressable elements 102. Accordingly, if an out of focus condition is detected, the focus may be corrected for each individually addressable element 102 or for a plurality of individually addressable elements 102. Focus may be corrected by, for example, moving lens 122 in a Z-direction (and/or about the X-axis and/or about the Y-axis).
In an embodiment, the sensor is integral with an individually addressable element 102 (or may be integral with a plurality of individually addressable elements 102). For example, a focus detection beam may be redirected (e.g., reflected) off the substrate surface, pass through the lens 122 and is directed toward a detector by a half-silvered mirror between the lens 122 and the individually addressable element 102. In an embodiment, the focus detection beam may be radiation used for exposure that happens to be redirected from the substrate. In an embodiment, the focus detection beam may be a dedicated beam directed at the substrate and which, upon redirected by the substrate, becomes the beam. A knife edge (which may be an aperture) may be provided in the path of the beam before the beam impinges on the detector. In this example, the detector comprises at least two radiation-sensitive parts (e.g., areas or detectors). When the substrate is in focus, a sharp image is formed at the edge and so the radiation-sensitive parts of the detector receive equal amounts of radiation. When the substrate is out of focus, the beam shifts and the image would form in front of or behind the edge. Thus, the edge would intercept certain parts of the beam and one radiation-sensitive part of the detector would receive a smaller amount of radiation than an other radiation-sensitive part of the detector. A comparison of the output signals from the radiation-sensitive parts of the detector enables the amount by which, and the direction in which, the plane of the substrate from which the beam redirected differs from a desired position. The signals may be electronically processed to give a control signal by which, for example, lens 122 may be adjusted. The mirror, edge and detector may be mounted to the array 230. In an embodiment, the detector may be a quad cell.
In an embodiment, there are no optics between the patterning device 104 and the substrate 114 other than a lens array 170. Thus, the lithographic apparatus 100 comprises a patterning device 104 and a projection system 108. In this case, the projection system 108 only comprises an array of lenses 170 arranged to receive the modulated radiation beam 110. Different portions of the modulated radiation beam 110, corresponding to one or more of the individually controllable elements in the patterning device 104, pass through respective different lenses in the array of lenses 170. Each lens focuses the respective portion of the modulated radiation beam 110 to a point that lies on the substrate 114. In this way an array of radiation spots S (see
Each of the individually controllable elements 102 provides a beam to a moving optical element 250 via, for example, deflector 112. In an embodiment, the individually controllable elements 102 are associated with one or more collimating lenses to provide a collimated beam to the optical element 250. In an embodiment, the collimating lens(es) is substantially stationary in the X-Y plane and attached to the frame to which the individually controllable elements 102 are attached.
In this embodiment, the cross-sectional width of the collimated beams are smaller than the cross-sectional width of the optical elements 250. So, for example, as soon as a collimated beam would fall completely within the optically transmissive portion of an optical element 250, the individually controllable element 102 (e.g., the diode laser) can be switched on. The individually controllable element 102 (e.g., the diode laser) may be switched off when the beam falls outside of the optically transmissive portion of the optical element 250. In an embodiment, the beam from an individually controllable element 102 passes through a single optical element 250 at any one time. The resulting traversal of the optical element 250 with respect to the beam from an individually controllable element 102 yields an associated imaged line 256 on the substrate from each individually controllable element 102 that is turned on. In
In the
In an embodiment, each of the optical elements 250 should be identical because each individually controllable element 102 may be imaged by all the moving optical elements 250. In this embodiment, all the optical elements 250 are without the need to image a field although a higher NA lens is needed, for example, greater than 0.3, greater than 0.18, or greater than 0.15. With this single element optics, diffraction limited imaging is possible.
The focal point of the beam on the substrate is fixed to the optical axis of the optical element 250 independent of where the beam enters the optical element (see, e.g.,
In this embodiment, adjusting the focus by using an element that is not moving in the X-Y plane (e.g., at the individually controllable element 102) will likely cause vignetting. Accordingly, desired adjustment of focus should occur in the moving optical element 250. This accordingly may require an actuator of higher frequency than the moving optical element 250.
The two lenses 260, 262 are arranged in the optical path of the collimated beam from an individually controllable element 102 to the substrate, to make the beam towards the substrate telecentric. The lens 260, between the individually controllable element 102 and the lens 262, comprises two lenses 260A, 260B with substantially equal focal length. The collimated beam from the individually controllable element 102 is focused between the two lenses 260A, 260B such that lens 260B will collimate the beam towards the imaging lens 262. The imaging lens 262 images the beam onto the substrate.
In this embodiment, the lens 260 moves at a certain speed in the X-Y plane (e.g., certain revolutions per minute (RPM)) with respect to an individually controllable element 102. Thus, in this embodiment, the outgoing collimated beam from the lens 260 would have twice the speed in the X-Y plane as the moving imaging lens 262 if it were moving at the same speed as the lens 260. So, in this embodiment, the imaging lens 264 moves at a speed, different than that of lens 260, with respect to an individually controllable element 102. In particular, the imaging lens 262 is moved in the X-Y plane at twice the speed as the lens 260 (e.g., twice the RPM of the lens 260) so that the beams will be focused telecentrically on the substrate. This aligning of the outgoing collimated beam from the lens 260 to the imaging lens 262 is schematically shown in three example positions in
In this embodiment, adjusting the focus by using an element that is not moving in the X-Y plane (e.g., at the individually controllable element 102) will likely lead to loss of telecentricity and cause vignetting. Accordingly, desired adjustment of focus should occur in the moving optical element 250.
Further, in this embodiment, all the optical elements 250 are without the need to image a field. With this single element optics, diffraction limited imaging is possible. A duty cycle of about 65% is possible. In an embodiment, the lenses 264, 260A, 260B and 262 may comprise 2 aspherical and 2 spherical lenses.
Lens 270 is also substantially stationary in the X-Y plane and focuses the collimated beam to a field lens 272 (having, for example, a cross-sectional width (e.g., diameter) of 1.5 mm) of moving optical element 250. The lens 272 has a relatively large focal length (e.g., f=20 mm).
The field lens 272 of movable optical element 250 moves relative to the individually controllable elements 102 (e.g., rotates about an axis where the optical elements 250 are arranged at least partially in a circular manner). The field lens 272 directs the beam toward imaging lens 276 of the movable optical element 250. Like field lens 272, the imaging lens 276 moves relative to the individually controllable elements 102 (e.g., rotates about an axis where the optical elements 250 are arranged at least partially in a circular manner). In this embodiment, the field lens 272 moves at the substantially same speed as the imaging lens 276. A pair of field lens 272 and imaging lens 276 are aligned with respect to each other. The substrate moves in the X-direction.
Between field lens 272 and the imaging lens 276 is a lens 274. Lens 274 is substantially stationary in the X-Y plane and collimates the beam from field lens 272 to the imaging lens 276. The lens 274 has a relatively large focal length (e.g., f=20 mm).
In this embodiment, the optical axis of a field lens 272 should coincide with the optical axis of the corresponding imaging lens 274. The field lens 272 is designed such that the beam will be folded so that the chief ray of the beam that is collimated by the lens 274 coincides with the optical axis of the imaging lens 276. In this way the beam towards the substrate is telecentric.
Lenses 270 and 274 may be simple spherical lenses due to the large f-number. The field lens 272 should not affect the image quality and may also be a spherical element. In this embodiment, the collimating lens 806 and the imaging lens 276 are lenses without the need to image field. With this single element optics, diffraction limited imaging is possible. A duty cycle of about 65% is possible.
In this embodiment, the individually controllable elements 102, along with optional collimating lenses, are arranged in a ring. Two parabola mirrors 278, 280 reduce the ring of collimated beams from the individually controllable elements 102 to an acceptable diameter for the derotator 282. In
In this embodiment, each individually controllable element 102 is paired to an optical element 250. Therefore, it may not be possible to mount the individually controllable elements 102 on concentric rings and thus, full coverage across of the width of the substrate may not be obtained. A duty cycle of about 33% is possible. In this embodiment, the optical elements 250 are lenses without the need to image field.
Referring to
The field lens 272 (e.g., a spherical lens) of movable optical element 250 moves relative to the individually controllable elements 102 in direction 288 (e.g., rotates about an axis where the optical elements 250 are arranged at least partially in a circular manner). The field lens 272 directs the beam toward imaging lens 276 (e.g., an aspherical lens such as a double aspherical surface lens) of the movable optical element 250. Like field lens 272, the imaging lens 276 moves relative to the individually controllable elements 102 (e.g., rotates about an axis where the optical elements 250 are arranged at least partially in a circular manner). In this embodiment, the field lens 272 moves at the substantially same speed as the imaging lens 276.
The focal plane of the field lens 272 coincides at location 290 with the back focal plane of the imaging lens 276 which gives a telecentric in/telecentric out system. Contrary to the arrangement of
The focal length of the imaging lenses 276 is such that, with a NA of 0.2 at the substrate, these lenses will not become larger than the diameter of the field lenses 272. A focal length of the imaging lens 276 equal to the diameter of the field lens 272 will give a diameter of the imaging lens 276 that leaves enough space for mounting the imaging lens 276.
Due to the field angle, a slightly larger line than the pitch of the field lenses 272 can be written. This gives an overlap, also depending on the focal length of the imaging lens 276, between the imaged lines of neighboring individually controllable elements 102 on the substrate. Accordingly, the individually controllable elements 102 may be mounted on the same pitch as the optical elements 250 on, for example, one ring.
To avoid relatively small double aspherical imaging lenses 276, reduce the amount of optics of the moving optical elements 250 and to use standard laser diodes as individually controllable elements 102, there is a possibility in this embodiment to image multiple individually controllable elements 102 with a single lens set of the movable optical elements 250. As long as an individually controllable element 102 is telecentrically imaged on the field lens 272 of each movable optical element 250, the corresponding imaging lens 276 will re-image the beam from the individually controllable element 102 telecentrically on the substrate. If, for example 8 lines are written simultaneously, the field lens 272 diameter and the focal distance of the imaging lens 276 can be increased by a factor 8 with the same throughput while the amount of movable optical elements 250 can be decreased by a factor 8. Further, the optics that are substantially stationary in the X-Y plane could be reduced since a part of the optics needed for imaging the individually controllable elements 102 on the field lenses 272 could be common. Such an arrangement of 8 lines being written simultaneously by a single movable optical element 250 set is schematically depicted in
In this embodiment, it is also relatively easy to focus locally with an element that does not move along or in conjunction with movable optical elements 250. As long as the telecentric images of the individually controllable elements 102 on the field lens 272 are moved along the optical axis and kept telecentric, the focus of the images on the substrate will only change and the images will remain telecentric.
Embodiments are also provided below in numbered clauses:
1. A lithographic apparatus comprising:
a substrate holder constructed to hold and move a substrate;
a modulator configured to modulate a plurality of beams according to a desired pattern, the modulator comprising an array of electro-optical deflectors, the array extending substantially perpendicularly to an optical axis of the apparatus; and
a projection system configured to receive and project the modulated beams toward the movable substrate.
2. The lithographic apparatus of clause 1, further comprising, in use, a donor structure located between the modulator and the substrate and onto which, in use, the modulated beams impinge, the donor structure having a donor material layer transferable from the donor structure onto the substrate.
3. The lithographic apparatus of clause 2, wherein the donor material is a metal.
4. The lithographic apparatus of any of clauses 1-3, wherein the modulated beams, in use, impinge the substrate and cause material of the substrate to be ablated.
5. The lithographic apparatus of any of clauses 1-4, wherein an electro-optical deflector of the plurality of electro-optical deflectors comprises a prism of electro-optic material, the prism situated non-perpendicularly with respect to an incident beam on the entrance face of the prism.
6. The lithographic apparatus of any of clauses 1-5, wherein the electro-optical deflectors comprise a first set of electro-optical deflectors to deflect the beams in only a first direction and second set of electro-optical deflectors to deflect the beam in only a second different direction.
7. The lithographic apparatus of any of clauses 1-6, wherein an electro-optical deflector of the plurality of electro-optical deflectors comprises a plurality of prisms arranged in sequence along the beam path, each alternating prism having an opposite domain.
8. The lithographic apparatus of any of clauses 1-7, wherein an electro-optical deflector of the plurality of electro-optical deflectors comprise at least one selected from the following: LiNbO3, LiTaO3, KH2PO4 (KDP), or NH4H2PO4 (ADP).
9. The lithographic apparatus of any of clauses 1-8, wherein an electro-optical deflector of the plurality of electro-optical deflectors has a refractive index gradient material.
10. A lithographic apparatus, comprising:
a substrate holder constructed to hold a substrate;
a modulator configured to modulate a beam according to a desired pattern, the modulator comprising an electro-optical deflector having a refractive index gradient material; and
a projection system configured to receive and project the modulated beam toward a substrate.
11. The lithographic apparatus of clause 9 or clause 10, wherein the refractive index gradient material comprises potassium tantalite niobate.
12. The lithographic apparatus of any of clauses 1-11, further comprising a prism of substantially the same refractive index as the electro-optical deflector located at the entrance surface, or the exit surface, or both the entrance and exit surfaces of the electro-optical deflector.
13. A lithographic apparatus comprising:
a substrate holder constructed to hold a substrate;
a modulator configured to modulate a beam of radiation according to a desired pattern;
a projection system configured to receive and project the modulated beam toward the substrate; and
a controller configured to convert operation of the apparatus to use the modulated beam to perform at least two of the following: photolithography, material deposition or material removal.
14. The lithographic apparatus of clause 13, wherein the controller is configured to convert the operation between material deposition and material removal.
15. The lithographic apparatus of clause 14, wherein the controller is configured to convert the operation among photolithography, material deposition and material removal.
16. The lithographic apparatus of any of clauses 13-15, wherein the controller is configured to convert the operation to material deposition and the lithographic apparatus comprises, in use, a donor structure located between the modulator and the substrate, the donor structure having a donor material layer transferable from the donor structure onto the substrate.
17. A lithographic apparatus comprising:
a substrate holder constructed to hold a substrate;
a modulator configured to modulate a beam of radiation according to a desired pattern;
a projection system configured to receive and project the modulated beam toward the substrate; and
a donor structure support to movably support a donor structure at a location between the modulator and the substrate, the donor structure having a donor material layer transferable from the donor structure onto the substrate and the modulated beam, in use, impinges on the donor structure.
18. The lithographic apparatus of clause 17, wherein the donor structure support is movable with respect to the projection system.
19. The lithographic apparatus of clause 18, wherein the donor structure support is located on the substrate holder.
20. The lithographic apparatus of any of clauses 17-19, wherein the substrate is movable and the donor structure support is configured to move the donor structure with the substrate.
21. The lithographic apparatus of any of clauses 17-20, wherein the donor structure support is located on a frame above the substrate holder.
22. The lithographic apparatus of clause 21, wherein the donor structure support comprises a gas bearing comprising an inlet to supply gas to between the support and the donor structure and an outlet to remove gas from between the support and the donor structure.
23. The lithographic apparatus of any of clauses 16-22, wherein the donor material is a metal.
24. The lithographic apparatus of any of clauses 13-23, wherein the modulator comprises an electro-optical deflector.
25. The lithographic apparatus of any of clauses 10-24, wherein the modulator is configured to modulate a plurality of beams according to the desired pattern, the modulator comprising an array of electro-optical deflectors, the array extending substantially perpendicularly to an optical axis of the apparatus and the projection system is configured to receive and project the modulated beams toward the substrate.
26. The lithographic apparatus of any of clauses 1-25, comprising a controller configured to move the beam according to an efficient exposure mode where the modulator causes deflection of the beams in the X- and Y-directions while the substrate is moving during exposure using the beams.
27. The lithographic apparatus of any of clauses 1-26, wherein the projection system comprises an array of lenses to receive the plurality of beams.
28. The lithographic apparatus of clause 27, wherein each lens comprises at least two lenses arranged along a beam path of at least one of the plurality of beams from the modulator toward the substrate.
29. The lithographic apparatus of clause 28, wherein a first lens of the at least two lenses comprises a field lens and a second lens of the at least two lenses comprises an imaging lens.
30. The lithographic apparatus of clause 29, wherein the focal plane of the field lens coincides with the back focal plane of the imaging lens.
31. The lithographic apparatus of clause 28 or clause 29, wherein a plurality of the beams are imaged with a single combination of the field lens and the imaging lens.
32. The lithographic apparatus of any of clauses 29-31, further comprising a lens to focus at least one of the plurality of beams toward the first lens.
33. The lithographic apparatus of any of clauses 1-32, wherein the array of lenses are movable with respect to the modulator.
34. The lithographic apparatus of any of clauses 1-33, wherein the modulator comprises a radiation source.
35. The lithographic apparatus of clause 34, wherein the modulator comprises a plurality of individually controllable radiation sources to emit electromagnetic radiation.
36. A beam deflection system, comprising an electro-optical deflector having a refractive index gradient material and a prism of substantially the same refractive index as the deflector at the entrance surface, or the exit surface, or both the entrance and exit surfaces of the deflector.
37. The beam deflection system of clause 36, wherein the refractive index gradient material comprises potassium tantalite niobate.
38. The beam deflection system of clause 36 or clause 37, further comprising:
a substrate holder constructed to hold a substrate;
a modulator configured to modulate a beam according to a desired pattern, the modulator comprising the electro-optical deflector; and
a projection system configured to receive and project the modulated beam toward a substrate.
39. A device manufacturing method comprising:
providing a plurality of beams modulated according to a desired pattern using an array of electro-optical deflectors, the array extending across the beam path of the beams;
projecting the plurality of beams toward a substrate; and
moving the substrate while projecting the beams.
40. A device manufacturing method comprising:
modulating a beam of radiation according to a desired pattern;
projecting the beam toward a substrate; and
converting use of the modulated beam to perform at least two of the following: photolithography, material deposition or material removal.
41. A device manufacturing method comprising:
modulating a beam of radiation according to a desired pattern;
projecting the beam toward a substrate; and
movably supporting a donor structure onto which the beam impinges, the donor structure having a donor material layer transferable from the donor structure onto the substrate.
42. A device manufacturing method comprising:
modulating a beam of radiation according to a desired pattern using an electro-optical deflector having a refractive index gradient material; and
projecting the beam toward a substrate.
43. A lithographic apparatus comprising:
a substrate holder constructed to hold a substrate;
a modulator configured to modulate a beam of radiation according to a desired pattern;
a projection system configured to receive and project the modulated beam toward the substrate; and
a donor structure transport system to move a donor structure at a location between the modulator and the substrate, the donor structure having a donor material layer transferable from the donor structure onto the substrate and the modulated beam, in use, impinges on the donor structure.
44. The lithographic apparatus of clause 43, wherein the donor structure is moved vertically between the modulator and the substrate.
45. The lithographic apparatus of clause 43 or clause 44, wherein the donor structure is flexible and the donor structure transport system comprises a roller to push or pull the flexible donor structure.
46. The lithographic apparatus of any of clauses 43-45, wherein the donor transport system forms a loop to circulate the donor structure within the apparatus.
47. The lithographic apparatus of any of clauses 43-48, wherein the donor transport rotates the donor structure into or out of the location.
48. The lithographic apparatus of any of clauses 43-48, wherein the donor structure comprises a plurality of donor structures moved by the transport system.
49. The lithographic apparatus of clause 48, wherein the transport system comprises a plurality of transport mechanisms, each mechanism associated with an optical engine of the apparatus.
50. The lithographic apparatus of any of clauses 43-49, comprising a regeneration module to apply donor material to the donor structure.
51. The lithographic apparatus of clause 50, wherein the regeneration module is configured to apply donor material to the donor structure while the donor structure is in the donor structure transport system.
52. The lithographic apparatus of clause 50 or clause 51, wherein the regeneration module comprises a compartment to strip donor material from the donor structure and a compartment to provide donor material on the donor structure.
53. The lithographic apparatus of clause 52, wherein the compartment to strip donor material is separated from the compartment to provide donor material.
54. The lithographic apparatus of any of clauses 50-53, wherein the regeneration module comprises an inkjet or similar apparatus to selectively apply donor material to the donor structure.
55. The lithographic apparatus of any of clauses 50-53, wherein the regeneration module comprises a vessel to expose the donor structure to a liquid or gas comprising donor material.
56. The lithographic apparatus of any of clauses 50-53, wherein the regeneration module is configured to use plasma deposition or electrolytical deposition of donor material.
57. The lithographic apparatus of any of clauses 43-56, wherein the donor material comprises a solvent and further comprising a heater to heat the substrate such that the solvent is evaporated by the heated substrate.
58. The lithographic apparatus of clause 57, further comprising a structure having an aperture located between the donor structure and the substrate holder, the donor material passing through the aperture from the donor structure to the substrate.
59. The lithographic apparatus of any of clauses 43-54, wherein the donor structure comprising an electrostatic or electromagnetic clamping body and the donor material comprises an electrostatic or electromagnetically clampable material.
60. The lithographic apparatus of clause 59, wherein the electrostatic or electromagnetically clampable material comprises particles of donor material.
61. A method to regenerate a donor structure having a donor material layer transferable from the donor structure onto the substrate when a beam impinges on the donor structure, the method comprising selectively applying donor material to the donor structure according to a pattern.
62. The method of clause 61, wherein the pattern corresponds to a pattern of holes in the donor material layer on the donor structure.
63. The method of clause 61 or clause 62, further comprising heating the donor structure to reflow the donor material on the donor structure.
64. The method of clause 61, further comprising stripping the donor structure of donor material prior to application of the selectively applied donor material.
65. The method of clause 64, wherein the pattern corresponds to a desired pattern to be deposited onto the substrate.
66. A device manufacturing method comprising:
modulating a beam of radiation according to a desired pattern; and
projecting the beam toward a donor structure having a donor material layer electrostatically or electromagnetically adhered thereto, the beam on impingement on the donor structure causing a portion of the donor material to transfer from the donor structure onto the substrate.
67. The method of clause 66, wherein the donor material comprises particles.
68. The method of clause 66 or clause 67, further comprising, after the projecting, stripping the donor structure of remaining donor material layer and applying a new electrostatically or electromagnetically adhered donor material layer to the donor structure.
69. The method of any of clauses 66-68, wherein the donor material layer is in a pattern form generally corresponding to the desired pattern.
70. A donor structure to transfer a donor material layer onto a substrate when a beam impinges on the donor structure, the donor structure comprising a patterned material having a high surface tension area and a low surface tension area.
71. The donor structure of clause 70, further comprising a donor material, the donor material adhering to the high surface tension area.
72. The donor structure of clause 71, wherein the donor material comprises a liquid having particles of donor material therein, the liquid evaporating to leave the particles on the high surface tension area.
73. The donor structure of any of clauses 70-72, wherein the patterned material has a first side and a second side on which donor material adheres and comprising a structure having an aperture between the first side and the second side.
74. The donor structure of any of clauses 70-73, wherein the patterned material comprises a transparent material of high surface tension material.
75. The donor structure of any of clauses 70-74, wherein the patterned material comprises a layer of low surface tension material having an aperture therein.
76. A lithographic apparatus comprising:
a substrate holder constructed to hold a substrate;
a source of liquid metal material; and
an inkjet apparatus to jet liquid metal material onto the substrate in a pattern.
77. The lithographic apparatus of clause 76, further comprising a heater to heat the substrate and the liquid metal material comprises a solvent evaporated by the heated substrate.
78. The lithographic apparatus of clause 76 or clause 77, further comprising a structure having an aperture located between the inkjet apparatus and the substrate holder, the jetted liquid material passing through the aperture to the substrate.
79. A device manufacturing method comprising:
modulating a beam of radiation according to a desired pattern;
projecting the beam toward a substrate, the substrate having a layer of material thereon; and
impinging the beam on a portion of the layer of the substrate, the beam causing the portion of the layer to change state from solid to liquid or from liquid to solid to form a pattern comprising the portion.
80. The device manufacturing method of clause 79, wherein the portion is changed from solid to liquid and subsequently changed to a solid or gel form.
81. The device manufacturing method of clause 80, wherein the layer comprises a metal powder.
82. The device manufacturing method of any of clauses 79-81, further comprising removing a portion of the layer not impinged by the beam to form a patterned structure comprising the portion of the layer.
83. A device manufacturing method comprising:
modulating a beam of radiation according to a desired pattern;
projecting the beam toward a substrate, the substrate having a first layer and a second layer on top of the first layer; and
impinging the beam on a portion of the second layer, the beam causing a property of the first layer under the portion to change to allow the overlying portion of second layer to deposit on the substrate.
84. The device manufacturing method of clause 83, wherein the property comprises changing the state of the first layer.
85. The device manufacturing method of clause 83 or clause 84, wherein the first layer comprises a plastic.
86. The device manufacturing method of clause 85, wherein the second layer comprises a metal.
87. The device manufacturing method of any of clauses 83-86, further comprising removing a portion of the first and second layers not impinged by the beam to form a patterned structure comprising the portion of the second layer deposited on the substrate.
88. Use of one or more of the embodiments of the invention in the manufacture of flat panel displays.
89. Use of one or more of the embodiments of the invention in integrated circuit packaging.
90. A flat panel display manufactured according to or using any of the embodiments of the invention.
91. An integrated circuit device manufactured according to or using any of the embodiments of the invention.
Although specific reference may be made in this text to the use of a lithographic apparatus in the manufacture of a specific device or structure (e.g. an integrated circuit or a flat panel display), it should be understood that the lithographic apparatus and lithographic method described herein may have other applications. Applications include, but are not limited to, the manufacture of integrated circuits, integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, LCDs, OLED displays, thin film magnetic heads, micro-electromechanical devices (MEMS), micro-opto-electromechanical systems (MOEMS), DNA chips, packaging (e.g., flip chip, redistribution, etc.), flexible displays or electronics (which are displays or electronics that may be rollable, bendable like paper and remain free of deformities, conformable, rugged, thin, and/or lightweight, e.g., flexible plastic displays), etc. Also, for instance in a flat panel display, the present apparatus and method may be used to assist in the creation of a variety of layers, e.g. a thin film transistor layer and/or a color filter layer. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms “wafer” or “die” herein may be considered as synonymous with the more general terms “substrate” or “target portion,” respectively. The substrate referred to herein may be processed, before or after exposure, in for example a track (e.g., a tool that typically applies a layer of resist to a substrate and develops the exposed resist) or a metrology or inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already contains multiple processed layers.
A flat panel display substrate may be rectangular in shape. A lithographic apparatus designed to expose a substrate of this type may provide an exposure region which covers a full width of the rectangular substrate, or which covers a portion of the width (for example half of the width). The substrate may be scanned underneath the exposure region, while the patterning device synchronously provides the patterned beam. In this way, all or part of the desired pattern is transferred to the substrate. If the exposure region covers the full width of the substrate then exposure may be completed with a single scan. If the exposure region covers, for example, half of the width of the substrate, then the substrate may be moved transversely after the first scan, and a further scan is typically performed to expose the remainder of the substrate.
The term “patterning device”, used herein should be broadly interpreted as referring to any device that can be used to modulate the cross-section of a radiation beam such as to create a pattern in (part of) the substrate. It should be noted that the pattern imparted to the radiation beam may not exactly correspond to the desired pattern in the target portion of the substrate, for example if the pattern includes phase-shifting features or so called assist features. Similarly, the pattern eventually generated on the substrate may not correspond to the pattern formed at any one instant by the array of individually controllable elements. This may be the case in an arrangement in which the eventual pattern formed on each part of the substrate is built up over a given period of time or a given number of exposures during which the pattern provided by the array of individually controllable elements and/or the relative position of the substrate changes. Generally, the pattern created on the target portion of the substrate will correspond to a particular functional layer in a device being created in the target portion, e.g., an integrated circuit or a flat panel display (e.g., a color filter layer in a flat panel display or a thin film transistor layer in a flat panel display). Examples of such patterning devices include, e.g., reticles, programmable mirror arrays, laser diode arrays, light emitting diode arrays, grating light valves, and LCD arrays. Patterning devices whose pattern is programmable with the aid of an electronic devices (e.g., a computer), e.g., patterning devices comprising a plurality of programmable elements that can each modulate the intensity of a portion of the radiation beam, (e.g., all the devices mentioned in the previous sentence except for the reticle), including electronically programmable patterning devices having a plurality of programmable elements that impart a pattern to the radiation beam by modulating the phase of a portion of the radiation beam relative to adjacent portions of the radiation beam, are collectively referred to herein as “contrast devices”. In an embodiment, the patterning device comprises at least 10 programmable elements, e.g. at least 100, at least 1000, at least 10000, at least 100000, at least 1000000, or at least 10000000 programmable elements. Embodiments of several of these devices are discussed in some more detail below:
A programmable mirror array. The programmable mirror array may comprise a matrix-addressable surface having a viscoelastic control layer and a reflective surface. The basic principle behind such an apparatus is that, for example, addressed areas of the reflective surface reflect incident radiation as diffracted radiation, whereas unaddressed areas reflect incident radiation as undiffracted radiation. Using an appropriate spatial filter, the undiffracted radiation can be filtered out of the reflected beam, leaving only the diffracted radiation to reach the substrate. In this manner, the beam becomes patterned according to the addressing pattern of the matrix-addressable surface. As an alternative, the filter may filter out the diffracted radiation, leaving the undiffracted radiation to reach the substrate. An array of diffractive optical MEMS devices may also be used in a corresponding manner. A diffractive optical MEMS device may comprise a plurality of reflective ribbons that may be deformed relative to one another to form a grating that reflects incident radiation as diffracted radiation. A further embodiment of a programmable mirror array employs a matrix arrangement of tiny mirrors, each of which may be individually tilted about an axis by applying a suitable localized electric field, or by employing piezoelectric actuation means. The degree of tilt defines the state of each mirror. The mirrors are controllable, when the element is not defective, by appropriate control signals from the controller. Each non-defective element is controllable to adopt any one of a series of states, so as to adjust the intensity of its corresponding pixel in the projected radiation pattern. Once again, the mirrors are matrix-addressable, such that addressed mirrors reflect an incoming radiation beam in a different direction to unaddressed mirrors; in this manner, the reflected beam may be patterned according to the addressing pattern of the matrix-addressable mirrors. The required matrix addressing may be performed using suitable electronic means. More information on mirror arrays as here referred to can be gleaned, for example, from U.S. Pat. No. 5,296,891 and U.S. Pat. No. 5,523,193, and PCT Patent Application Publication Nos. WO 98/38597 and WO 98/33096, which are incorporated herein by reference in their entirety.
The lithographic apparatus may comprise one or more patterning devices, e.g. one or more contrast devices. For example, it may have a plurality of arrays of individually controllable elements, each controlled independently of each other. In such an arrangement, some or all of the arrays of individually controllable elements may have at least one of a common illumination system (or part of an illumination system), a common support structure for the arrays of individually controllable elements and/or a common projection system (or part of the projection system).
Where pre-biasing of features, optical proximity correction features, phase variation techniques and/or multiple exposure techniques are used, for example, the pattern “displayed” on the array of individually controllable elements may differ substantially from the pattern eventually transferred to a layer of or on the substrate. Similarly, the pattern eventually generated on the substrate may not correspond to the pattern formed at any one instant on the array of individually controllable elements. This may be the case in an arrangement in which the eventual pattern formed on each part of the substrate is built up over a given period of time or a given number of exposures during which the pattern on the array of individually controllable elements and/or the relative position of the substrate changes.
The projection system and/or illumination system may include various types of optical components, e.g., refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, to direct, shape, or control the beam of radiation.
The lithographic apparatus may be of a type having two (e.g., dual stage) or more substrate tables (and/or two or more patterning device tables). In such “multiple stage” machines the additional table(s) may be used in parallel, or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposure.
The lithographic apparatus may also be of a type wherein at least a portion of the substrate may be covered by an “immersion liquid” having a relatively high refractive index, e.g. water, so as to fill a space between the projection system and the substrate. An immersion liquid may also be applied to other spaces in the lithographic apparatus, for example, between the patterning device and the projection system. Immersion techniques are used to increase the NA of projection system. The term “immersion” as used herein does not mean that a structure, e.g., a substrate, must be submerged in liquid, but rather only means that liquid is located between the projection system and the substrate during exposure.
Further, the apparatus may be provided with a fluid processing cell to allow interactions between a fluid and irradiated parts of the substrate (e.g., to selectively attach chemicals to the substrate or to selectively modify the surface structure of the substrate).
In an embodiment, the substrate has a substantially circular shape, optionally with a notch and/or a flattened edge along part of its perimeter. In an embodiment, the substrate has a polygonal shape, e.g. a rectangular shape. Embodiments where the substrate has a substantially circular shape include embodiments where the substrate has a diameter of at least 25 mm, for instance at least 50 mm, at least 75 mm, at least 100 mm, at least 125 mm, at least 150 mm, at least 175 mm, at least 200 mm, at least 250 mm, or at least 300 mm. In an embodiment, the substrate has a diameter of at most 500 mm, at most 400 mm, at most 350 mm, at most 300 mm, at most 250 mm, at most 200 mm, at most 150 mm, at most 100 mm, or at most 75 mm. Embodiments where the substrate is polygonal, e.g. rectangular, include embodiments where at least one side, e.g. at least 2 sides or at least 3 sides, of the substrate has a length of at least 5 cm, e.g. at least 25 cm, at least 50 cm, at least 100 cm, at least 150 cm, at least 200 cm, or at least 250 cm. In an embodiment, at least one side of the substrate has a length of at most 1000 cm, e.g. at most 750 cm, at most 500 cm, at most 350 cm, at most 250 cm, at most 150 cm, or at most 75 cm. In an embodiment, the substrate is a rectangular substrate having a length of about 250-350 cm and a width of about 250-300 cm The thickness of the substrate may vary and, to an extent, may depend, e.g., on the substrate material and/or the substrate dimensions. In an embodiment, the thickness is at least 50 μm, for instance at least 100 μm, at least 200 μm, at least 300 μm, at least 400 μm, at least 500 μm, or at least 600 μm. In one embodiment, the thickness of the substrate is at most 5000 μm, for instance at most 3500 μm, at most 2500 μm, at most 1750 μm, at most 1250 μm, at most 1000 μm, at most 800 μm, at most 600 μm, at most 500 μm, at most 400 μm, or at most 300 μm. The substrate referred to herein may be processed, before or after exposure, in for example a track (a tool that typically applies a layer of resist to a substrate and develops the exposed resist). Properties of the substrate may be measured before or after exposure, for example in a metrology tool and/or an inspection tool.
In an embodiment, a resist layer is provided on the substrate. In an embodiment, the substrate is a wafer, for instance a semiconductor wafer. In an embodiment, the wafer material is selected from the group consisting of Si, SiGe, SiGeC, SiC, Ge, GaAs, InP, and InAs. In an embodiment, the wafer is a III/V compound semiconductor wafer. In an embodiment, the wafer is a silicon wafer. In an embodiment, the substrate is a ceramic substrate. In an embodiment, the substrate is a glass substrate. Glass substrates may be useful, e.g., in the manufacture of flat panel displays and liquid crystal display panels. In an embodiment, the substrate is a plastic substrate. In an embodiment, the substrate is transparent (for the naked human eye). In an embodiment, the substrate is colored. In an embodiment, the substrate is absent a color.
While, in an embodiment, the patterning device 104 is described and/or depicted as being above the substrate 114, it may instead or additionally be located under the substrate 114. Further, in an embodiment, the patterning device 104 and the substrate 114 may be side by side, e.g., the patterning device 104 and substrate 114 extend vertically and the pattern is projected horizontally. In an embodiment, a patterning device 104 is provided to expose at least two opposite sides of a substrate 114. For example, there may be at least two patterning devices 104, at least on each respective opposing side of the substrate 114, to expose those sides. In an embodiment, there may be a single patterning device 104 to project one side of the substrate 114 and appropriate optics (e.g., beam directing mirrors) to project a pattern from the single patterning device 104 onto another side of the substrate 114.
In the description herein, the term “lens” should be understood generally to encompass any refractive, reflective, and/or diffractive optical element that provides the same function as the referenced lens. For example, an imaging lens may be embodied in the form of a conventional refractive lens having optical power, in the form of a Schwarzschild reflective system having optical power, and/or in the form of a zone plate having optical power. Moreover, an imaging lens may comprise non-imaging optics if the resulting effect is to produce a converged beam.
While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the invention may take the form of a computer program containing one or more sequences of machine-readable instructions describing a method as disclosed above, or a data storage medium (e.g. semiconductor memory, magnetic or optical disk) having such a computer program stored therein.
Moreover, although this invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. For example, it is contemplated that various combination or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. For example, in an embodiment, the movable individually controllable elements may be combined with a non-movable array of individually controllable elements, for example, to provide or have a back-up system. In an embodiment, one or more features or aspects disclosed in U.S. patent application publication no. US 201 1-01 8801 6 and PCT patent application publication no. WO 2010/032224, the entire contents of U.S. patent application publication no. US 201 1-01 8801 6 and PCT patent application publication no. WO 2010/032224 incorporated herein by reference, may be combined with or substituted for one or more features or aspects disclosed herein.
Thus, while various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
This application claims the benefit of U.S. provisional application 61/524,190, filed on Aug. 16, 2011. This provisional application is hereby incorporated in its entirety by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2012/064270 | 7/20/2012 | WO | 00 | 1/16/2014 |
| Number | Date | Country | |
|---|---|---|---|
| 61524190 | Aug 2011 | US |
