Patent Grant
9182222
The present invention relates to a lithographic apparatus and in particular to an immersion lithographic apparatus and a method of substrate placement in an immersion lithographic apparatus.
A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that instance, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. comprising part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
It has been proposed to immerse the substrate in the lithographic projection apparatus in a liquid having a relatively high refractive index, e.g., water, so as to fill a space between the final element of the projection system and the substrate. The point of this is to enable imaging of smaller features since the exposure radiation will have a shorter wavelength in the liquid. (The effect of the liquid may also be regarded as increasing the effective numerical aperture (NA) of the system and also increasing the depth of focus.) Other immersion liquids have been proposed, including water with solid particles (e.g., quartz) suspended therein.
However, submersing the substrate or substrate and substrate table in a bath of liquid (see for example U.S. Pat. No. 4,509,852, hereby incorporated in its entirety by reference) means that there is a large body of liquid that must be accelerated during a scanning exposure. This requires additional or more powerful motors and turbulence in the liquid may lead to undesirable and unpredictable effects.
One of the solutions proposed is for a liquid supply system to provide liquid on only a localized area of the substrate and in between the final element of the projection system and the substrate (the substrate generally has a larger surface area than the final element of the projection system). One way which has been proposed to arrange for this is disclosed in PCT patent application no. WO 99/49504, hereby incorporated in its entirety by reference. As illustrated in
An aspect of the present invention is to provide a method for determining an offset between a center of a substrate and a center of a depression in a chuck. The method includes providing a test substrate to the depression, the test substrate having a dimension smaller than a dimension of the depression, measuring a position of an alignment mark of the test substrate while in the depression and determining the offset between the center of the substrate and the center of the depression from the position of the alignment mark.
In an embodiment of the invention, providing the test substrate to the depression includes loading the test substrate with a substrate handler inside the depression.
In an embodiment of the invention, measuring the position of the alignment mark of the test substrate comprises measuring the position of the alignment mark relative to a reference mark of the chuck or vice versa.
The method may further comprise determining a position of the center of the depression relative to a position of a reference mark of the chuck or vice versa, and determining a position of the center of the test substrate relative to the position of the alignment mark of the test substrate or vice versa.
In an embodiment of the invention, measuring the position of the center of the test substrate can be performed with a prealigner.
In an embodiment of the invention, the dimension of the test substrate is such that, when the test substrate is in the depression, a gap between an edge of the test substrate and an edge of the depression is greater than a maximum offset.
In an embodiment of the invention, measuring the position of the alignment mark of the test substrate is performed with an optical system. The optical system may include, for example, an interferometer and an optical alignment system.
The method may further comprise calibrating a substrate handler to take into account the offset.
In an embodiment of the invention, calibrating the substrate handler includes shifting a positioning of substrates by the substrate handler to correct for the offset so that a subsequent substrate provided by the substrate handler to the depression is substantially centered inside the depression.
Another aspect of the present invention is to provide a method for determining an offset between a center of a substrate and a center of a depression in a chuck. The method includes measuring a gap between an edge of the substrate disposed inside the depression and an edge of the depression at a plurality of locations, determining a center of the substrate using the measurements of the gap, and determining a chuck centering offset of the substrate between the center of the depression and the measured center of the substrate at the chuck. The method further includes providing the substrate to a prealigner and determining a center of the substrate at the prealigner, determining a prealigner centering offset between a nominal center of the substrate and the measured center of the substrate at the prealigner, and combining the chuck centering offset and the prealigner centering offset to obtain a global centering offset.
The method may further include determining a position of the edge of the depression and calculating a center of the depression.
In an embodiment of the invention, determining the chuck centering offset includes determining the position of the center of the substrate relative to the position of the center of the depression.
In an embodiment of the invention, measuring the gap includes scanning the gap across an optical beam and measuring an intensity variation in a reflection of the optical beam.
In an embodiment of the invention, determining the center of the substrate using the measurements of the gap includes determining a position of the edge of the substrate and calculating the position of the center of the substrate from the position of the edge.
In an embodiment of the invention, the substrate can be disposed inside the depression and can be removed from the depression using a substrate handler.
The method may further include calibrating the substrate handler to take into account the global centering offset.
In an embodiment of the invention, calibrating the substrate handler includes shifting positioning of substrates by the substrate handler by an offset to correct for the global centering offset so that a subsequently positioned substrate is substantially centered inside the depression.
In an embodiment of the invention, calibrating the substrate handler includes correcting for substrate positioning so that the gap of a subsequently positioned substrate is equally wide inside the depression.
A further aspect of the present invention is to provide a method for determining an offset between a center of a substrate and a center of a depression in a chuck. The method includes loading the substrate on a pin of the chuck and moving the substrate by translating the pin in a first direction until the substrate reaches an opening of the depression in the chuck, determining to what extent the substrate should be translated in a plane substantially perpendicular to the first direction to allow the substrate to enter inside the depression without colliding with a surface of the chuck or an edge of the depression in the chuck, and determining the offset of the substrate relative to the depression from determination of the translation in the plane.
In an embodiment of the invention, determining to what extent the substrate should be translated includes translating the substrate, in the plane on the pin relative to the chuck, translating the chuck, in the plane, relative to the substrate or the pin, or both, until a footprint of the substrate would fit into the depression.
In an embodiment of the invention loading the substrate on a pin of the chuck is performed with a substrate handler.
The method may also include calibrating the substrate handler to take into account the offset.
In an embodiment of the invention, calibrating the substrate handler includes shifting positioning of substrates by of the substrate handler by an amount to correct for the offset so that a subsequently positioned substrate is substantially centered inside the depression.
In an embodiment of the invention, calibrating the substrate handler includes correcting for substrate positioning so that the gap of a subsequently positioned substrate is equally wide inside the depression.
Another aspect of the present invention is to provide a lithographic projection apparatus. The lithographic apparatus includes a support structure configured to hold a patterning device. The patterning device is configured to pattern a beam of radiation according to a desired pattern. The lithographic apparatus also includes a substrate table configured to hold a substrate. The substrate table has a depression for receiving the substrate. The lithographic apparatus has a projection system configured to project the patterned beam onto a target portion of the substrate. The lithographic apparatus also includes a liquid supply system configured to provide a liquid, through which the patterned beam is to be projected, in a space between the projection system and the substrate and a sensor configured to measure a position of the substrate, a sensor configured to measure a gap between an edge of the substrate disposed inside the depression and an edge of the depression, or a sensor configured to measure both the position and the gap. The lithographic apparatus further includes a substrate handling system in communication with the sensor configured to position the substrate inside the depression such that the gap between the edge of the substrate and the edge of the depression is substantially uniform inside the depression.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:
an illumination system (illuminator) IL configured to condition a radiation beam PB (e.g. UV radiation or DUV radiation);
a support structure (e.g. a mask table) MT constructed to support a patterning device (e.g. a mask) MA and connected to a first positioner PM configured to accurately position the patterning device in accordance with certain parameters;
a substrate table (e.g. a wafer table) WT constructed to hold a substrate (e.g. a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate in accordance with certain parameters; and
a projection system (e.g. a refractive projection lens system) PL configured to project a pattern imparted to the radiation beam PB by patterning device MA onto a target portion C (e.g. comprising one or more dies) of the substrate W.
The illumination system may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, for directing, shaping, or controlling radiation.
The support structure supports, i.e. bears the weight of, the patterning device. It holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions, such as for example whether or not the patterning device is held in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure may be a frame or a table, for example, which may be fixed or movable as required. The support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system. Any use of the terms “reticle” or “mask” herein may be considered synonymous with the more general term “patterning device.”
The term “patterning device” used herein should be broadly interpreted as referring to any device that can be used to impart a radiation beam with a pattern in its cross-section such as to create a pattern in a target portion 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. Generally, the pattern imparted to the radiation beam will correspond to a particular functional layer in a device being created in the target portion, such as an integrated circuit.
The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography, and include mask types such as binary, alternating phase-shift, and attenuated phase-shift, as well as various hybrid mask types. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted so as to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern in a radiation beam which is reflected by the mirror matrix.
The term “projection system” used herein should be broadly interpreted as encompassing any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, or for other factors such as the use of an immersion liquid or the use of a vacuum. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system”.
As here depicted, the apparatus is of a transmissive type (e.g. employing a transmissive mask). Alternatively, the apparatus may be of a reflective type (e.g. employing a programmable mirror array of a type as referred to above, or employing a reflective mask).
The lithographic apparatus may be of a type having two (dual stage) or more substrate tables (and/or two or more mask tables). In such “multiple stage” machines the additional tables 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.
Referring to
The illuminator IL may comprise an adjuster AD for adjusting the angular intensity distribution of the radiation beam. 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. In addition, the illuminator IL may comprise various other components, such as an integrator IN and a condenser CO. The illuminator may be used to condition the radiation beam, to have a desired uniformity and intensity distribution in its cross-section.
The radiation beam PB is incident on the patterning device (e.g., mask MA), which is held on the support structure (e.g., mask table MT), and is patterned by the patterning device. Having traversed the mask MA, the radiation beam PB passes through the projection system PL, which focuses the beam onto a target portion C of the substrate W. An immersion hood IH, which is described further below, supplies immersion liquid to a space between the final element of the projection system PL and the substrate W.
With the aid of the second positioner PW and position sensor IF (e.g. an interferometric device, linear encoder or capacitive sensor), the substrate table WT can be moved accurately, e.g. so as to position different target portions C in the path of the radiation beam PB. Similarly, the first positioner PM and another position sensor (which is not explicitly depicted in
Similarly, in situations in which more than one die is provided on the mask MA, the mask alignment marks may be located between the dies.
The depicted apparatus could be used in at least one of the following modes:
1. In step mode, the mask table MT and the substrate table WT are kept essentially stationary, while an entire pattern imparted to the radiation beam is projected onto a target portion C at one time (i.e. a single static exposure). The substrate table WT is then shifted in the X and/or Y direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.
2. In scan mode, the mask table MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto a target portion C (i.e. a single dynamic exposure). The velocity and direction of the substrate table WT relative to the mask table MT may be determined by the (de-)magnification and image reversal characteristics of the projection system PL. 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 another mode, the mask table MT is kept essentially stationary holding a programmable patterning device, and the substrate table WT is moved or scanned while a pattern imparted to the radiation beam is projected onto a target portion C. In this mode, generally a pulsed radiation source is employed and the programmable patterning device is updated as required after each movement of the substrate table WT or in between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above.
Combinations and/or variations on the above described modes of use or entirely different modes of use may also be employed.
A further immersion lithography solution with a localized liquid supply system is shown in
Another immersion lithography solution with a localized liquid supply system solution which has been proposed is to provide the liquid supply system with a seal member which extends along at least a part of a boundary of the space between the final element of the projection system and the substrate table. Such a solution is illustrated in
Referring to
The liquid is confined in the reservoir by a gas seal 16 between the bottom of the seal member 12 and the surface of the substrate W. The gas seal is formed by gas, e.g. air or synthetic air but, in an embodiment, N2 or another inert gas, provided under pressure via inlet 15 to the gap between seal member 12 and substrate and extracted via first outlet 14. The overpressure on the gas inlet 15, vacuum level on the first outlet 14 and geometry of the gap are arranged so that there is a high-velocity gas flow inwards that confines the liquid. Such a system is disclosed in U.S. patent application Ser. No. 10/705,783, hereby incorporated in its entirety by reference.
The reservoir 10 between the final element of the projection system and the substrate which is filled with liquid may come close to an edge of the substrate W during the scanning operation of the substrate. In order to limit or prevent liquid leakage when exposing an edge of the substrate, the substrate is arranged such that an upper surface of the substrate W is at substantially a same level as the substrate table (or chuck) WT, as illustrated in
As shown in more detail in
In an implementation, a gap G between the edge 20 of the substrate W and the edge 22 of the depression DP, of for example 0.5 mm, is made available to all sides of a well-centered substrate W. Due to, for example, inaccuracies of the substrate hander in handling and positioning the substrate inside the depression in the chuck, however, the substrate may not be perfectly centered, as illustrated in
In conventional lithographic projection apparatus, i.e., non-immersion lithographic projection apparatus, it is not required to correct an offset between the substrate center and the chuck center during placement of the substrate on the chuck. The substrate W is loaded and positioned on the chuck and then the offset between centers (if not already partially corrected during placement of the substrate of the chuck) can be corrected to the expected position of the substrate itself.
In an immersion lithographic projection apparatus, however, the substrate W is disposed inside the depression DP in the chuck WT and the offset Δ as discussed above can be as much as 0.6 mm, for example. This may lead to the situation where one edge, for example edge 20L, of the substrate 20 is distant from an edge, for example edge 22L, of the depression DP by as much as 1.0 mm. This gap G1 on one side of 1.0 mm corresponds to the initial G gap on one side of 0.5 mm (if the substrate is well-centered inside the depression) compounded with an offset Δ of 0.5 mm. This gap G1 of 1.0 mm at one side of the substrate may be too large which may lead to seepage of liquid through this gap and/or may lead to instability of the gas seal hovering on top of the gap G1. This may be particularly undesirable in lithography because this may require removal of the substrate and cleaning of the substrate and substrate table which leads inevitably to slowing down of the production process or may lead to instability of the gas seal which would also lead to problems in holding the liquid in place.
In addition, if, for example, the offset Δ is 0.6 mm, the substrate edge 20R can hit the edge 22R of the depression DP because the offset Δ of 0.6 mm is greater than the supposed available G gap of 0.5 mm if the substrate W was well-centered (Δ>G). In this condition, the substrate W cannot be loaded inside the depression DP. This situation is also undesirable because any error in the placement of a substrate W during manufacturing may lead to a downtime of the machine resulting in loss of productivity.
Therefore, it is desired to determine the offset Δ of the substrate W inside the depression DP so that the substrate handling system can be calibrated to take into account the offset so that the above unwanted situation or situations may be prevented. If the offset of the substrate inside the depression is determined and the substrate handling system calibrated to take into account the offset, it may be possible the tailor the dimension(s) of the depression so that the substrate fits more precisely in the depression and as a result the gap can be further minimized.
In an embodiment, a method for determining the offset between the center of the substrate and the center of the depression is to use a slightly smaller test substrate W than the depression DP and then a normal production substrate to ensure that the test substrate W can be loaded by the substrate handler independent of the size of the offset. For example, the dimension of the test substrate W can be selected such that the gap G (for example 1.0 mm) is greater than a maximum offset Δ (for example 0.6 mm), i.e., G>Δmax. In this situation, even if the offset is maximum, e.g., equal to 0.6 mm, the test substrate W would still be able to be placed inside the depression DP because an offset of 0.6 mm is smaller than a gap G of 1.0 mm. The substrate handler loads the test substrate W with the intention that it is centered in the depression DP (even though there may in fact be an unknown offset). With the test substrate disposed inside the depression DP, the determination and calibration of the offset can be performed.
Referring to
In addition, or alternatively, the lithographic apparatus may have nominal positions for where the alignment mark AM and the fiducial mark FM should be located for proper centering of the test substrate W. Once the test substrate W is disposed in the depression DP, the actual positions of the alignment mark AM and the fiducial mark FM can be determined and the offset Δ can be determined from the difference between the nominal and actual positions.
By knowing the offset Δ in the positioning of the test substrate W, the substrate handler can be calibrated to take into account the offset Δ. In particular, the position of the mechanism of the substrate handler may be calibrated so that any position of a substrate by the substrate handler may correct for the offset. In this manner, subsequent loads of production substrates onto the substrate table will be properly centered in the depression DP.
In another embodiment, a method for determining the offset Δ between the center of the substrate and the center of the depression is, for example, to “manually” dispose a typical production substrate W in the depression DP to ensure that the substrate W is inside the depression DP. By “manually” disposing is meant that the substrate W is in the depression DP. This may be done, for example, by a technician putting the substrate W in the depression DP, by the normal operation of the substrate handler if the substrate W properly goes into the depression DP, by combination of normal operation of the substrate handler W and subsequent adjustments made to the position of the substrate W by, e.g., the substrate handler so that the substrate W is properly disposed in the depression DP or by any other means.
With the substrate disposed inside the depression DP, as shown in
In an alternative or additional embodiment, the position of the edge of the substrate W at a plurality of locations can be measured directly using, for example, an intensity variation at a scanning radiation beam of a level sensor and the position of the impact of that beam on the substrate/substrate table determined from an interferometer measurement of the position of the substrate table.
The position of the center CD of the depression DP in the coordinate system of the chuck can either be known from other measurements or can be also determined by measurements of the edge of the depression DP. With the knowledge of the position of the center CS of the substrate and the position of the center CD of the depression, the chuck centering offset of the substrate W in the depression DP, i.e., in the chuck coordinate system, can be determined. The chuck centering offset Δ can, for example, be determined by calculating the position of the center CS of the substrate W relative to the position of the center CD of the depression DP.
Subsequently, the substrate W is provided, by using a substrate handler, to a prealigner and the position of the center CS of the substrate W is measured with the prealigner. The prealigner has a nominal center of the substrate W in the pre-aligner coordinate system. A pre-aligner centering offset can be determined between the normal and measured centers of the substrate W in the prealigner coordinate system. The chuck centering offset in the chuck coordinate system and the prealigner center of offset in the prealigner coordinate system are then combined and a global offset is calculated. The substrate handler is calibrated to take into account the global offset. In the calibration of the substrate handler, the positioning, i.e., coordinate system, of substrates by the substrate handler is corrected to take account of the global offset so that the gap of a substrate subsequently positioned in the depression is equally wide and thus the substrate is substantially centered inside the depression.
A chuck is typically provided with a substrate displacement mechanism that includes at least one pin. The mechanism is used to displace the substrate onto the chuck or to displace the substrate from the chuck. The substrate is positioned on and/or carried away from the substrate replacement mechanism, or the chuck itself, by a substrate handler. The substrate handler is typically a motor driven robot arm that has a fork for carrying the substrate. In the case of an immersion lithographic apparatus, the pin or pins are provided inside the depression in the chuck so that the substrate can be displaced into and out of the depression.
In an embodiment of the invention, a method for determining the offset between the center of the substrate W and the center of the depression DP is to load a substrate W on a pin or pins of the chuck WT, as shown in
With the offset Δ, the substrate handler can be calibrated to take into account the offset Δ. In the calibration of the substrate handler, the positioning of a substrate W by the substrate handler is shifted by the offset Δ to correct for the offset Δ so that a subsequent substrate loaded by the substrate handler to the chuck WT is centered inside the depression DP. As a result, subsequent substrate loads are positioned correctly on the pin(s) for positioning substrates centrally inside the depression without likelihood of collision with a surface of the chuck.
In an embodiment, there is provided a method for determining an offset between a center of a substrate and a center of a depression in a chuck, comprising: providing a test substrate to the depression, the test substrate having a dimension smaller than a dimension of the depression; measuring a position of an alignment mark of the test substrate while in the depression; and determining the offset between the center of the substrate and the center of the depression from the position of the alignment mark.
In an embodiment, providing the test substrate to the depression comprises loading the test substrate inside the depression using a substrate handler. In an embodiment, measuring the position of the alignment mark of the test substrate comprises measuring the position of the alignment mark relative to a reference mark of the chuck or vice versa. In an embodiment, the method further comprises determining a position of the center of the depression relative to a position of a reference mark of the chuck or vice versa; and determining a position of the center of the test substrate relative to the position of the alignment mark of the test substrate or vice versa. In an embodiment, measuring the position of the center of the test substrate is performed with a prealigner. In an embodiment, the dimension of the test substrate is such that, when the test substrate is in the depression, a gap between an edge of the test substrate and an edge of the depression is greater than a maximum offset. In an embodiment, measuring the position of the alignment mark of the test substrate is performed with an optical system. In an embodiment, the optical system comprises an interferometer and an optical alignment system. In an embodiment, the method further comprises calibrating a substrate handler to take into account the offset. In an embodiment, calibrating the substrate handler includes shifting a positioning of substrates by the substrate handler to correct for the offset so that a subsequent substrate provided by the substrate handler to the depression is substantially centered inside the depression.
In an embodiment, there is provided a method for determining an offset between a center of a substrate and a center of a depression in a chuck, comprising: measuring a gap between an edge of the substrate disposed inside the depression and an edge of the depression at a plurality of locations; determining a center of the substrate using the measurements of the gap; determining a chuck centering offset of the substrate between the center of the depression and the measured center of the substrate at the chuck; providing the substrate to a prealigner and determining a center of the substrate at the prealigner; determining a prealigner centering offset between a nominal center of the substrate and the measured center of the substrate at the prealigner; and combining the chuck centering offset and the prealigner centering offset to obtain a global centering offset.
In an embodiment, the method further comprises determining a position of the edge of the depression and calculating a center of the depression. In an embodiment, determining the chuck centering offset comprises determining the position of the center of the substrate relative to the position of the center of the depression. In an embodiment, measuring the gap comprises scanning the gap across an optical beam and measuring an intensity variation in a reflection of the optical beam. In an embodiment, determining the center of the substrate using the measurements of the gap comprises determining a position of the edge of the substrate and calculating the position of the center of the substrate from the position of the edge. In an embodiment, the substrate is disposed inside the depression and removed from the depression using a substrate handler. In an embodiment, the method further comprises calibrating the substrate handler to take into account the global centering offset. In an embodiment, calibrating the substrate handler includes shifting positioning of substrates by the substrate handler by an offset to correct for the global centering offset so that a subsequently positioned substrate is substantially centered inside the depression. In an embodiment, calibrating the substrate handler includes correcting for substrate positioning so that the gap of a subsequently positioned substrate is equally wide inside the depression.
In an embodiment, there is provided a method for determining an offset between a center of a substrate and a center of a depression in a chuck, comprising: loading the substrate on a pin of the chuck and moving the substrate by translating the pin in a first direction until the substrate reaches an opening of the depression in the chuck; determining to what extent the substrate should be translated in a plane substantially perpendicular to the first direction to allow the substrate to enter inside the depression without colliding with a surface of the chuck or an edge of the depression in the chuck; and determining the offset of the substrate relative to the depression from determination of the translation in the plane.
In an embodiment, determining to what extent the substrate should be translated comprises translating the substrate, in the plane on the pin relative to the chuck, translating the chuck, in the plane, relative to the substrate or the pin, or both, until a footprint of the substrate would fit into the depression. In an embodiment, loading the substrate on a pin of the chuck is performed with a substrate handler. In an embodiment, the method further comprises calibrating the substrate handler to take into account the offset. In an embodiment, calibrating the substrate handler includes shifting positioning of substrates by of the substrate handler by an amount to correct for the offset so that a subsequently positioned substrate is substantially centered inside the depression. In an embodiment, calibrating the substrate handler includes correcting for substrate positioning so that the gap of a subsequently positioned substrate is equally wide inside the depression.
In an embodiment, there is provided lithographic projection apparatus comprising: a support structure configured to hold a patterning device, the patterning device configured to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate, the substrate table having a depression configured to receive the substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; a liquid supply system configured to provide a liquid, through which the patterned beam is to be projected, in a space between the projection system and the substrate; a sensor configured to measure a position of the substrate, a sensor configured to measure a gap between an edge of the substrate disposed inside the depression and an edge of the depression, or a sensor configured to measure both the position and the gap; and a substrate handling system in communication with the sensor configured to position the substrate inside the depression such that the gap between the edge of the substrate and the edge of the depression is substantially uniform inside the depression.
In an embodiment, the substrate handling system is configured to be calibrated to correct for an offset between the substrate and the depression. In an embodiment, the substrate handling system is configured to determine an offset between a center of the substrate and a center of the depression. In an embodiment, the sensor configured to measure the position of the substrate is configured to measure a position of an alignment mark of a test substrate disposed inside the depression, and wherein the substrate handling system is configured to determine an offset between a center of the test substrate and a center of the depression from the position of the alignment mark measured by the sensor. In an embodiment, the substrate handling system is configured to determine to what extent the substrate should be translated in a plane substantially parallel to the substrate table to allow the substrate to enter inside the depression without colliding with a surface of the substrate table or an edge of the depression. In an embodiment, the substrate handling system is configured to determine an offset between the substrate and the depression from determination of the translation in the plane. In an embodiment, the substrate handling system is configured to determine a center of the substrate using measurements of the gap and to determine an offset of the substrate between a center of the depression and the measured center of the substrate. In an embodiment, the apparatus further comprises a prealigner configured to measure a center of the substrate at the prealigner and wherein the substrate handling system is configured to determine a centering offset at the prealigner between a nominal center of the substrate and the measured center of the substrate at the prealigner. In an embodiment, the substrate handling system is configured to combine the offset of the substrate and the centering offset to obtain a global centering offset.
In European Patent Application No. 03257072.3, the idea of a twin or dual stage immersion lithography apparatus is disclosed. Such an apparatus is provided with two tables for supporting a substrate. Leveling measurements are carried out with a table at a first position, without immersion liquid, and exposure is carried out with a table at a second position, where immersion liquid is present. Alternatively, the apparatus has only one table.
Although specific reference may be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, liquid-crystal displays (LCDs), thin-film magnetic heads, etc. 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 (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology tool and/or an 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.
The terms “radiation” and “beam” used herein encompass all types of electromagnetic radiation, including ultraviolet (UV) radiation (e.g. having a wavelength of or about 365, 248, 193, 157 or 126 nm).
The term “lens”, where the context allows, may refer to any one or combination of various types of optical components, including refractive and reflective optical components.
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, where applicable, 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.
The present invention can be applied to any immersion lithography apparatus, in particular, but not exclusively, those types mentioned above. The immersion liquid used in the apparatus may have different compositions, according to the desired properties and the wavelength of exposure radiation used. For an exposure wavelength of 193 nm, ultra pure water or water-based compositions may be used and for this reason the immersion liquid is sometimes referred to as water and water-related terms such as hydrophilic, hydrophobic, humidity, etc. may be used.
The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.
The present application is a continuation of U.S. patent application Ser. No. 13/288,714, filed Nov. 3, 2011, now allowed, which is a divisional application of U.S. patent application Ser. No. 11/907,045, filed Oct. 9, 2007, now U.S. Pat. No. 8,077,291, which is a divisional application of U.S. patent application Ser. No. 11/008,576, filed Dec. 10, 2004, now U.S. Pat. No. 7,352,440, which is incorporated herein by reference in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3573975 | Dhaka et al. | Apr 1971 | A |
| 3648587 | Stevens | Mar 1972 | A |
| 4346164 | Tabarelli et al. | Aug 1982 | A |
| 4390273 | Loebach et al. | Jun 1983 | A |
| 4396705 | Akeyama et al. | Aug 1983 | A |
| 4480910 | Takanashi et al. | Nov 1984 | A |
| 4509852 | Tabarelli et al. | Apr 1985 | A |
| 5040020 | Rauschenbach et al. | Aug 1991 | A |
| 5121256 | Corle et al. | Jun 1992 | A |
| 5343049 | Vareille et al. | Aug 1994 | A |
| 5563798 | Berken et al. | Oct 1996 | A |
| 5610683 | Takahashi | Mar 1997 | A |
| 5633698 | Imai | May 1997 | A |
| 5715039 | Fukuda et al. | Feb 1998 | A |
| 5786897 | Ototake | Jul 1998 | A |
| 5825043 | Suwa | Oct 1998 | A |
| 5900354 | Batchelder | May 1999 | A |
| 6032512 | Li | Mar 2000 | A |
| 6126382 | Scales et al. | Oct 2000 | A |
| 6191429 | Suwa | Feb 2001 | B1 |
| 6197117 | Li et al. | Mar 2001 | B1 |
| 6236634 | Lee et al. | May 2001 | B1 |
| 6332751 | Kozawa et al. | Dec 2001 | B1 |
| 6342705 | Li et al. | Jan 2002 | B1 |
| 6400445 | Nishi et al. | Jun 2002 | B2 |
| 6405101 | Johanson et al. | Jun 2002 | B1 |
| 6516244 | Yoo et al. | Feb 2003 | B1 |
| 6600547 | Watson et al. | Jul 2003 | B2 |
| 6603130 | Bisschops et al. | Aug 2003 | B1 |
| 6903338 | Mankos et al. | Jun 2005 | B2 |
| 6906739 | Suzuki et al. | Jun 2005 | B2 |
| 6987593 | Hayashi et al. | Jan 2006 | B2 |
| 6990430 | Hosek | Jan 2006 | B2 |
| 7106412 | De Bokx et al. | Sep 2006 | B2 |
| 7301607 | Hazelton et al. | Nov 2007 | B2 |
| 7352440 | Hoogendam et al. | Apr 2008 | B2 |
| 7359031 | Klomp et al. | Apr 2008 | B2 |
| 7372538 | Binnard | May 2008 | B2 |
| 7417710 | Schreuder | Aug 2008 | B2 |
| 20010055117 | Mizutani | Dec 2001 | A1 |
| 20020020821 | Van Santen et al. | Feb 2002 | A1 |
| 20020057423 | Nogawa | May 2002 | A1 |
| 20020153477 | Hasegawa et al. | Oct 2002 | A1 |
| 20020163629 | Switkes et al. | Nov 2002 | A1 |
| 20030010887 | Potempka | Jan 2003 | A1 |
| 20030071982 | Miyajima et al. | Apr 2003 | A1 |
| 20030123040 | Almogy | Jul 2003 | A1 |
| 20030178145 | Anderson et al. | Sep 2003 | A1 |
| 20030227624 | Wu et al. | Dec 2003 | A1 |
| 20040000627 | Schuster | Jan 2004 | A1 |
| 20040075895 | Lin | Apr 2004 | A1 |
| 20040114117 | Bleeker | Jun 2004 | A1 |
| 20040136494 | Lof et al. | Jul 2004 | A1 |
| 20040143412 | Donald | Jul 2004 | A1 |
| 20040149906 | Mankos et al. | Aug 2004 | A1 |
| 20040151574 | Lu | Aug 2004 | A1 |
| 20040160582 | Lof et al. | Aug 2004 | A1 |
| 20040165159 | Lof et al. | Aug 2004 | A1 |
| 20040167743 | Hosek | Aug 2004 | A1 |
| 20040207824 | Lof et al. | Oct 2004 | A1 |
| 20040211920 | Derksen et al. | Oct 2004 | A1 |
| 20040212791 | De Bokx et al. | Oct 2004 | A1 |
| 20040239954 | Bischoff | Dec 2004 | A1 |
| 20040263809 | Nakano | Dec 2004 | A1 |
| 20050007569 | Streefkerk et al. | Jan 2005 | A1 |
| 20050016818 | Ito et al. | Jan 2005 | A1 |
| 20050018155 | Cox et al. | Jan 2005 | A1 |
| 20050024609 | De Smit et al. | Feb 2005 | A1 |
| 20050030497 | Nakamura | Feb 2005 | A1 |
| 20050046813 | Streefkerk et al. | Mar 2005 | A1 |
| 20050046934 | Ho et al. | Mar 2005 | A1 |
| 20050052632 | Miyajima | Mar 2005 | A1 |
| 20050094116 | Flagello et al. | May 2005 | A1 |
| 20050094125 | Arai | May 2005 | A1 |
| 20050122505 | Miyajima | Jun 2005 | A1 |
| 20050132914 | Mulkens et al. | Jun 2005 | A1 |
| 20050134817 | Nakamura | Jun 2005 | A1 |
| 20050140948 | Tokita | Jun 2005 | A1 |
| 20050146693 | Ohsaki | Jul 2005 | A1 |
| 20050146694 | Tokita | Jul 2005 | A1 |
| 20050151942 | Kawashima | Jul 2005 | A1 |
| 20050200815 | Akamatsu | Sep 2005 | A1 |
| 20050213065 | Kitaoka | Sep 2005 | A1 |
| 20050213066 | Sumiyoshi | Sep 2005 | A1 |
| 20050219489 | Nei et al. | Oct 2005 | A1 |
| 20050233081 | Tokita | Oct 2005 | A1 |
| 20050259234 | Hirukawa et al. | Nov 2005 | A1 |
| 20050264774 | Mizutani et al. | Dec 2005 | A1 |
| 20060110836 | Devany et al. | May 2006 | A1 |
| 20060126038 | Hoogendam et al. | Jun 2006 | A1 |
| 20060137988 | Yahashi et al. | Jun 2006 | A1 |
| 20070037301 | Jekauc | Feb 2007 | A1 |
| 20070070312 | Schreuder | Mar 2007 | A1 |
| 20070216893 | Yasuda | Sep 2007 | A1 |
| 20070242242 | Nagasaka et al. | Oct 2007 | A1 |
| 20080151257 | Yasuda et al. | Jun 2008 | A1 |
| 20080318152 | Mizutani | Dec 2008 | A1 |
| 20100143832 | Houben | Jun 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 206 607 | Feb 1984 | DE |
| 221 563 | Apr 1985 | DE |
| 224 448 | Jul 1985 | DE |
| 242 880 | Feb 1987 | DE |
| 0023231 | Feb 1981 | EP |
| 0418427 | Mar 1991 | EP |
| 0 597 637 | May 1994 | EP |
| 0 634 785 | Jul 1994 | EP |
| 1039511 | Sep 2000 | EP |
| 1 063 186 | Dec 2000 | EP |
| 1 134 618 | Sep 2001 | EP |
| 1571696 | Dec 2003 | EP |
| 1571697 | Dec 2003 | EP |
| 1 420 299 | May 2004 | EP |
| 1 429 188 | Jun 2004 | EP |
| 1 447 716 | Aug 2004 | EP |
| 1 571 697 | Sep 2005 | EP |
| 2474708 | Jul 1981 | FR |
| 58-202448 | Nov 1983 | JP |
| 59-19912 | Feb 1984 | JP |
| 62-065326 | Mar 1987 | JP |
| 62-121417 | Jun 1987 | JP |
| 63-157419 | Jun 1988 | JP |
| H02-271643 | Nov 1990 | JP |
| 04-305915 | Oct 1992 | JP |
| 04-305917 | Oct 1992 | JP |
| 05-62877 | Mar 1993 | JP |
| 05-299322 | Nov 1993 | JP |
| 06-124873 | May 1994 | JP |
| 07-132262 | May 1995 | JP |
| 07-220990 | Aug 1995 | JP |
| 07-288276 | Oct 1995 | JP |
| 08-167549 | Jun 1996 | JP |
| 08-316125 | Nov 1996 | JP |
| H10-041372 | Feb 1998 | JP |
| 10-228661 | Aug 1998 | JP |
| 10-255319 | Sep 1998 | JP |
| 410247681 | Sep 1998 | JP |
| 10-303114 | Nov 1998 | JP |
| 10-340846 | Dec 1998 | JP |
| 11-176727 | Jul 1999 | JP |
| 2000-058436 | Feb 2000 | JP |
| 2001-091849 | Apr 2001 | JP |
| 2001-358063 | Dec 2001 | JP |
| 2003-243294 | Aug 2003 | JP |
| 2004-027696 | Jul 2004 | JP |
| 2004-186306 | Jul 2004 | JP |
| 2004-193252 | Jul 2004 | JP |
| 2004-207710 | Jul 2004 | JP |
| 2004-235149 | Aug 2004 | JP |
| 2004-259966 | Sep 2004 | JP |
| WO 9949504 | Sep 1999 | WO |
| 2004019128 | Mar 2004 | WO |
| 2004019128 | Mar 2004 | WO |
| 2004053596 | Jun 2004 | WO |
| 2004053950 | Jun 2004 | WO |
| 2004053951 | Jun 2004 | WO |
| 2004053952 | Jun 2004 | WO |
| 2004053953 | Jun 2004 | WO |
| 2004053954 | Jun 2004 | WO |
| 2004053955 | Jun 2004 | WO |
| 2004053956 | Jun 2004 | WO |
| 2004053957 | Jun 2004 | WO |
| 2004053958 | Jun 2004 | WO |
| 2004053959 | Jun 2004 | WO |
| 2004053954 | Jun 2004 | WO |
| 2004055803 | Jul 2004 | WO |
| 2004057589 | Jul 2004 | WO |
| 2004057590 | Jul 2004 | WO |
| 2004090577 | Oct 2004 | WO |
| 2004090633 | Oct 2004 | WO |
| 2004090634 | Oct 2004 | WO |
| 2004092830 | Oct 2004 | WO |
| 2004092833 | Oct 2004 | WO |
| 2004093130 | Oct 2004 | WO |
| 2004093159 | Oct 2004 | WO |
| 2004093160 | Oct 2004 | WO |
| 2004090577 | Oct 2004 | WO |
| 2004095135 | Nov 2004 | WO |
| 2005010611 | Feb 2005 | WO |
| 2005010611 | Feb 2005 | WO |
| 2005024517 | Mar 2005 | WO |
| Entry |
|---|
| M. Switkes et al., “Immersion Lithography at 157 nm”, MIT Lincoln Lab, Orlando 2001-1, Dec. 17, 2001. |
| M. Switkes et al., “Immersion Lithography at 157 nm”, J. Vac. Sci. Technol. B., vol. 19, No. 6, Nov./Dec. 2001, pp. 2353-2356. |
| M. Switkes et al., “Immersion Lithography: Optics for the 50 nm Node”, 157 Anvers-1, Sep. 4, 2002. |
| IDS filed Apr. 4, 2007 for U.S. Appl. No. 11/730,915. |
| B.J. Lin, “Drivers, Prospects and Challenges for Immersion Lithography”, TSMC, Inc., Sep. 2002. |
| B.J. Lin, “Proximity Printing Through Liquid”, IBM Technical Disclosure Bulletin, vol. 20, No. 11B, Apr. 1978, p. 4997. |
| B.J. Lin, “The Paths to Subhalf-Micrometer Optical Lithography”, SPIE vol. 922, Optical/Laser Microlithography (1988), pp. 256-269. |
| G.W.W. Stevens, “Reduction of Waste Resulting from Mask Defects”, Solid State Technology, Aug. 1978, vol. 21 008, pp. 68-72. |
| S. Owa et al., “Immersion Lithography; its potential performance and issues”, SPIE Microlithography 2003, 5040-186, Feb. 27, 2003. |
| S. Owa et al., “Advantage and Feasibility of Immersion Lithography”, Proc. SPIE 5040 (2003). |
| Office Action in related European Application No. 05 257 411.8 mailed Aug. 15, 2011. |
| Non-Final Office Action as issued for U.S. Appl. No. 12/071,254, dated Mar. 17, 2009. |
| Non-Final Office Action as issued for U.S. Appl. No. 12/071,254, dated Jan. 6, 2010. |
| Non-Final Office Action as issued for U.S. Appl. No. 11/683,743, dated May 20, 2010. |
| Information Disclosure Statement as filed for U.S. Appl. No. 12/701,014, dated Feb. 5, 2010. |
| Information Disclosure Statement as filed for U.S. Appl. No. 12/071,262, dated Feb. 19, 2008. |
| H. Hogan, “New Semiconductor Lithography Makes a Splash”, Photonics Spectra, Photonics TechnologyWorld, Oct. 2003 Edition, pp. 1-3. |
| S. Owa and N. Nagasaka, “Potential Performance and Feasibility of Immersion Lithography”, NGL Workshop 2003, Jul. 10, 2003, Slide Nos. 1-33. |
| English translation of Taiwanese Official Action, and Search Report completed on Mar. 17, 2009, issued in Taiwanese Application No. 094141774. |
| Australian Search Report issued on Dec. 11, 2008 in Singapore Application No. 200704377-1. |
| Nikon Precision Europe GmbH, “Investor Relations—Nikon's Real Solutions”, May 15, 2003. |
| H. Kawata et al., “Optical Projection Lithography using Lenses with Numerical Apertures Greater than Unity”, Microelectronic Engineering 9 (1989), pp. 31-36. |
| J.A. Hoffnagle et al., “Liquid Immersion Deep-Ultraviolet Interferometric Lithography”, J. Vac. Sci. Technol. B., vol. 17, No. 6, Nov./Dec. 1999, pp. 3306-3309. |
| B.W. Smith et al., “Immersion Optical Lithography at 193nm”, FUTURE FAB International, vol. 15, Jul. 11, 2003. |
| H. Kawata et al., “Fabrication of 0.2μm Fine Patterns Using Optical Projection Lithography with an Oil Immersion Lens”, Jpn. J. Appl. Phys. vol. 31 (1992), pp. 4174-4177. |
| G. Owen et al., “⅛μm Optical Lithography”, J. Vac. Sci. Technol, B., vol. 10, No. 6, Nov./Dec. 1992, pp. 3032-3036. |
| Non-Final Office Action as issued for U.S. Appl. No. 12/071,262, dated Aug. 20, 2008. |
| Non-Final Office Action as issued for U.S. Appl. No. 12/071,262, dated Jun. 3, 2009. |
| Final Office Action as issued for U.S. Appl. No. 12/071,262, dated Mar. 17, 2010. |
| Search Report for European Application No. No. 05257411.8-2222, dated Mar. 21, 2006. |
| Search Report for European Application No. 05257411.8-1226 issued May 7, 2007. |
| S. Owa et al., “Update on 193nm immersion exposure tool”, Litho Forum, International SEMATECH, Los Angeles, Jan. 27-29, 2004, Slide Nos. 1-51. |
| H. Hata, “The Development of Immersion Exposure Tools”, Litho Forum, International Sematech, Los Angeles, Jan. 27-29, 2004, Slide Nos. 1-22. |
| T. Matsuyama et al., “Nikon Projection Lens Update”, SPIE Microlithography 2004, 5377-65, Mar. 2004. |
| “Depth-of-Enhancement Using High Refractive Index Layer on the Imaging Layer”, IBM Technical Disclosure Bulletin, vol. 27, No. 11, Apr. 1985, p. 6521. |
| A. Suzuki, “Lithography Advances on Multiple Fronts”, EEdesign, EE Times, Jan. 5, 2004. |
| B. Lin, The k3 coefficient in nonparaxial Λ/NA scaling equations for resolution, depth of focus, and immersion lithography, J. Microlith., Microfab., Microsyst. 1(1):7-12 (2002). |
| R. Bernhardt et al., “Robot Calibration,” Kluwer, The Language of Science, 4 pages (Oct. 31, 1993). |
| Michael P. Deisenroth at al., “Part 4: Programming and Intelligence. Chapter 18: On-Line Programming,” Handbook of Industrial Robotics, Second Edition, pp. 337-349 (Mar. 1999). |
| Number | Date | Country | |
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| 20130182231 A1 | Jul 2013 | US |
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| Parent | 13288714 | Nov 2011 | US |
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