Patent Application
20200209757
This application claims priority of EP application 16180675.7 which was filed on 22 Jul. 2016 and which is incorporated herein in its entirety by reference.
The present invention relates to a lithographic apparatus, a lithographic projection apparatus and a method for manufacturing a device in which use is made of a 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 such a case, 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. including 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. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at once, 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.
A lithographic apparatus often comprises a projection system which comprises at least one optical element such as a mirror or a lens. An illumination system conditions a beam of radiation which is sent to a patterning device. From the patterning device, the beam enters the projection system, which transfers the radiation beam to a substrate.
The optical element needs to be accurately positioned relative to at least the radiation beam in order to achieve the desired projection accuracy, and therewith to reduce overlay error in the image on the substrate.
Optionally, the projection system comprises multiple optical elements. In that case, the position of the optical elements relative to each other needs to be accurately controlled in order to obtain the desired projection accuracy. This position control becomes more complicated when it is desired that one or more of the optical elements perform a scanning motion, for example in order to compensate for thermal expansion of the substrate.
It is desirable to provide a lithographic apparatus and a lithographic projection apparatus which allows to obtain a good projection accuracy.
According to an embodiment of the invention, a lithographic apparatus is provided which comprises:
In another embodiment of the invention, a lithographic apparatus is provided which comprises:
In another embodiment of the invention, a lithographic projection apparatus is provided which is arranged to project a pattern from a patterning device onto a substrate, which lithographic projection apparatus comprises:
In another embodiment of the invention, a device manufacturing method is provided comprising transferring a pattern from a patterning device onto a substrate, wherein use is made of a lithographic apparatus according to the invention.
In another embodiment of the invention, a device manufacturing method is provided comprising projecting a patterned beam of radiation onto a substrate, wherein use is made of a lithographic apparatus according to the invention.
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:
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 mask 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 mask support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The mask support structure may be a frame or a table, for example, which may be fixed or movable as required. The mask 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 so 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 minor 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 minor 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 or “substrate supports” (and/or two or more mask tables or “mask supports”). In such “multiple stage” machines the additional tables or supports may be used in parallel, or preparatory steps may be carried out on one or more tables or supports while one or more other tables or supports 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 a 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 mask and the projection system Immersion techniques can be used to increase the numerical aperture of projection systems. The term “immersion” as used herein does not mean that a structure, such as a substrate, must be submerged in liquid, but rather only means that a liquid is located between the projection system and the substrate during exposure.
Referring to
The illuminator IL may include an adjuster AD configured to adjust the angular intensity distribution of the radiation beam. Generally, at least the outer and/or inner radial extent (commonly referred to as a-outer and a-inner, respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted. In addition, the illuminator IL may include 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 B is incident on the patterning device (e.g., mask MA), which is held on the mask support structure (e.g., mask table MT), and is patterned by the patterning device. Having traversed the mask MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of the second positioning device 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 B. Similarly, the first positioning device PM and another position sensor (which is not explicitly depicted in
The depicted apparatus could be used in at least one of the following modes:
Combinations and/or variations on the above described modes of use or entirely different modes of use may also be employed.
The lithographic apparatus 1 comprises a base frame 10. The base frame 10 is adapted for mounting the lithographic apparatus 1 on a support surface 9. The support surface 9 can for example be a factory floor, a foundation or a pedestal. The base frame 10 is optionally arranged on the support surface by one or more supports, which is in
The lithographic apparatus 1 further comprises a projection system 20. The projection system 20 comprises at least one optical element 21, which in this example is a mirror.
The projection system 20 further comprises a force frame 30. In the embodiment shown in
The projection system 20 further comprises a sensor frame 40. The sensor frame 40 is separate from the force frame 30. The force frame 30 can therewith move independently from the sensor frame 40. When the force frame 30 is moved or deformed, this movement or deformation is not directly transferred to the sensor frame 40. This arrangement provides a further disconnection between the force frame 30 and the sensor frame 40, making that vibrations, forces and deformations of the force frame 30 are not, or at least to a lesser extent, transferred to the sensor frame 40.
The projection system further comprises a sensor. The sensor comprises at least one sensor element 25, which is arranged on the sensor frame 40. The sensor is adapted to monitor the optical element 21.
Optionally, the sensor is adapted to generate measurement data relating to the position of the optical element 21 relative to the sensor frame 40. The sensor can for example comprise an interferometric device, an encoder-based device (comprising e.g. a linear encoder) or a capacitive sensor.
The sensor optionally comprises a sensor sender/receiver element and a sensor target element. If the sensor is an encoder based device, the sensor optionally comprises a grating, e.g. a one dimensional or two dimensional grating, which is for example arranged on the optical element 21 and an encoder head, which comprises a beam source and at least one receiver element which is adapted to receive the beam from the grating, which encoder head is for example arranged on the sensor frame 40. Alternatively, the grating may be arranged on the sensor frame 40 and the encoder head may be arranged on the optical element 21.
If the sensor is interferometer based, the sensor comprises a mirror element which is for example arranged on the optical element 21, a source for an optical beam and a receiver which is adapted to receive the beam from the mirror element. The source for the optical beam is arranged such that the optical beam strikes the mirror element on the optical element 21. Alternatively, the mirror element may for example be arranged on the sensor frame 40.
The lithographic apparatus 1 further comprises a force frame support 31, which is adapted to support the force frame 30 on the base frame 10.
In addition, the lithographic apparatus 1 comprises an intermediate frame 45, which is separate from the force frame 30. The force frame 30 can therewith move independently from the intermediate frame 45. When the force frame 30 is moved or deformed, this movement or deformation is not directly transferred to the intermediate frame 45. This arrangement provides a further disconnection between the force frame 30 and the sensor frame 40, making that vibrations, forces and deformations of the force frame 30 are not, or at least to a lesser extent, transferred to the sensor frame 40. In the embodiment of
The sensor frame 40 is coupled to the intermediate frame 45 by a sensor frame coupler 41. The sensor frame coupler 41 may be for example be or comprise a sensor frame support with a vibration isolator, or a magnetic coupling device such as a magnetic gravity compensator.
The intermediate frame 45 is supported on the base frame 10 by an intermediate frame support 46, which is separate from the force fame support 31.
This arrangement makes that movement and deformation of the force frame 30, which are for example caused by movement of the optical element 21 relative to the force frame 30 (for example for the purpose of positioning the optical element 21 relative to the beam or to other optical elements of the projection system, or due to scanning movement that is imparted on the optical element 21), is not directly transferred to the sensor frame 40. This arrangement provides a further disconnection between the force frame 30 and the sensor frame 40, making that vibrations, forces and deformations of the force frame 30 are not, or at least to a lesser extent, transferred to the sensor frame 40. This increases the stability and position accuracy of the sensor frame 40, which for example allows to determine the position of the optical element 21 more accurately. A more accurate determination of the position of the optical element 21 allows to position the optical element 21 more accurately, which increases the projection accuracy and therewith reduces the overlay.
In addition, the vibration isolation from the force frame 30 relative to the base frame 10 and the vibration isolation of the sensor frame from the base frame 10 can both be optimised independently from each other. This allows specific optimisation of the vibration isolation of the force frame 30 and of the sensor frame 40 separately, taking into account the specific requirements and circumstances in each of these subsystems. For example, vibration isolation of the force frame 30 can be designed to accommodate a relatively large displacement of the optical element 21 (for example if a scanning motion of the optical element 21 is desired), while at same time the sensor frame 40 can be provided with a high level of vibration isolation at relatively low frequencies. By applying the current invention, there is no need to strike a compromise between those sometimes conflicting requirements.
Because the invention allows this kind of individual optimisation, the stability and positioning accuracy of the sensor frame 40 can be increased. Again, this allows to determine the position of the optical element 21 more accurately and a more accurate determination of the position of the optical element 21 allows to position the optical element 21 more accurately, which increases the projection accuracy and therewith reduces the overlay error.
In the embodiment of
Optionally, each vibration isolator 32, 42, 47 comprises a pneumatic vibration isolator device or a plurality of pneumatic vibration isolator devices. The use of pneumatic vibration isolator devices allows to choose a specific isolation frequency (above which the vibrations will be effectively damped) from a large range of available products, each having their specific combinations of product specifications, because pneumatic vibration isolator devices are readily available in many shapes and sizes.
Optionally, both the force frame support 31 and the intermediate frame support 46 comprise a vibration isolator 32, 47 having an isolation frequency. The vibration isolator effectively dampens vibrations above the isolation frequency, so that the vibration isolation is effective for vibrations having a frequency above the isolation frequency. The isolation frequency of the vibration isolator 32 of the force frame support 31 is optionally higher than the isolation frequency of the vibration isolator 47 of the intermediate frame support 46. This allows an effective vibration isolation of the sensor frame 40, starting already at relatively low frequencies. The requirements for vibration isolation in the low frequency range of the force frame 30 are not so strict as the requirements for vibration isolation in the low frequency range of the sensor frame 40, so the force frame support 31 can be provided with a simpler and/or cheaper vibration isolator.
Optionally, both the sensor frame coupler 41 and the intermediate frame support 46 comprise a vibration isolator 42,47 having a isolation frequency. The isolation frequency of the vibration isolator 42 of the sensor frame coupler 41 is optionally higher than the isolation frequency of the vibration isolator 47 of the intermediate frame support 46. The vibration isolation of the sensor frame 40 is therewith a two-step arrangement, which allows to optimize the design of the vibration isolation. This arrangement of having two vibration isolators 42, 47 in series provides increased isolation for vibrations with a high frequency.
Optionally, the lithographic apparatus 1 in accordance with
The force frame position sensor 51 is adapted to generate measurement data relating to the position of the force frame 30 relative to the sensor frame 40. The force frame position sensor 51 can for example comprise an interferometric device, an encoder-based device (comprising e.g. a linear encoder) or a capacitive sensor. Optionally, the force frame position sensor 51 comprises a plurality of sensor elements.
The force frame position sensor 51 optionally comprises a sensor sender/receiver element and a sensor target element. Optionally, the force frame position sensor comprises a plurality of sensor sender/receiver elements and sensor target elements. If the force frame position sensor 51 is an encoder based device, the sensor optionally comprises a grating, e.g. a one dimensional or two dimensional grating, which is for example arranged on the force frame 30 and an encoder head, which comprises a beam source and at least one receiver element which is adapted to receive the beam from the grating, which encoder head is for example arranged on the sensor frame 40. Alternatively, the grating may be arranged on the sensor frame 40 and the encoder head may be arranged on the force frame 30.
If the sensor is interferometer based, the sensor comprises a mirror element which is for example arranged on the force frame 30, a source for an optical beam and a receiver which is adapted to receive the beam from the mirror element. The source for the optical beam is arranged such that the optical beam strikes the mirror element on the force frame 30. Alternatively, the mirror element may for example be arranged on the sensor frame 40.
The force frame actuator 33 is adapted to move the force frame 30 relative to the sensor frame 40. Optionally, the force frame actuator 33 is integrated into the force frame support 31, which makes that the force frame support 31 is turned into an active support. The addition of the actuator makes that the force frame support is adapted to move the force frame 30 relative to the sensor frame 40 (and relative to the base frame 10), which allows to actively control the position of the force frame 30 relative to the sensor frame 40. This allows an increased positioning accuracy of the optical element 21, and therewith an improvement of the projection accuracy and a reduction of the overlay. The force frame actuator 33 is for example an electromagnetic actuator such as a Lorentz actuator or a reluctance actuator.
The force frame actuator control device 52 of the force frame control system 50 is adapted to receive the measurement data from the force frame position sensor 51 and to control the force frame actuator 33 based on the received measurement data.
Optionally, in the embodiment of
In the embodiment of
The base frame sections 10a, 10b are adapted for mounting the lithographic apparatus 1 on a support surface 9. The support surface 9 can for example be a factory floor, a foundation or a pedestal. The base frame sections 10a, 10b are optionally arranged on the support surface by one or more supports, which in
In the embodiment according to
In the embodiment of
The wafer stage 60 is adapted to support and position a substrate. The position of the wafer stage 60 needs to be monitored accurately. To that end, at least one position sensor is provided, e.g. an interferometer based sensor, an encoder based sensor and/or a capacitive sensor. The sensor each comprises at least one sensor element, which is arranged on the wafer stage measurement frame 61. Optionally, the lithographic apparatus according to
In the embodiment of
In the embodiment of
Optionally, in the embodiment according to
Optionally, the secondary intermediate frame support 63 comprises a vibration isolator 64. Optionally, the vibration isolator 64 comprises a pneumatic vibration isolator device or a plurality of pneumatic vibration isolator devices.
Optionally, in this embodiment, the base frame 10 comprises a third base frame section, to which the secondary intermediate frame support 63 is connected. The base frame optionally further comprises a first base frame section and a second base frame section. The first, second and third base frame sections are moveable relative to each other. Optionally, the first, second and third base frame sections are separate from each other. Alternatively, at least two of the first, second and third base frame sections may be connected to each other by a flexible connection, e.g. an elastic hinge. As a further alternative, at least two of the first, second and third base frame sections may be connected to each other by a connector comprising a vibration isolator. As a further alternative, at least two of the first, second and third base frame sections may be connected to each other by a deformable seal which is arranged to bridge a gap between the respective base frame sections. Optionally, the force frame support 31 is connected to the first base frame section and the intermediate frame support 46 is connected to the second base frame section.
Alternatively, the base frame 10 comprises a primary base frame section and a secondary base frame section. The primary and secondary base frame sections are moveable relative to each other. Optionally, the primary and secondary base frame sections are separate from each other. Alternatively, the primary and secondary base frame sections may be connected to each other by a flexible connection, e.g. an elastic hinge. As a further alternative, the primary and secondary base frame sections may be connected to each other by a connector comprising a vibration isolator. As a further alternative, the primary and secondary base frame sections may be connected to each other by a deformable seal which is arranged to bridge a gap between the respective base frame sections. Optionally, the force frame support 31 is connected to the primary base frame section and the secondary intermediate frame support 63 is connected to the secondary base frame section. Optionally, both the force frame support 31 and the secondary intermediate frame support 63 are connected to the primary base frame section and the intermediate frame support 46 is connected to the secondary base frame section.
Optionally, in the embodiment of
The secondary intermediate frame position sensor 71 is adapted to generate measurement data relating to the position of the secondary intermediate frame 45b relative to the sensor frame 40. The secondary intermediate frame position sensor 71 can for example comprise an interferometric device, an encoder-based device (comprising e.g. a linear encoder) or a capacitive sensor.
The secondary intermediate frame position sensor 71 optionally comprises a sensor sender/receiver element and a sensor target element. If the secondary intermediate frame position sensor 71 is an encoder based device, the sensor optionally comprises a grating, e.g. a one dimensional or two dimensional grating, which is for example arranged on the secondary intermediate frame 45b and an encoder head, which comprises a beam source and at least one receiver element which is adapted to receive the beam from the grating, which encoder head is for example arranged on the sensor frame 40. Alternatively, the grating may be arranged on the sensor frame 40 and the encoder head may be arranged on the secondary intermediate frame 45b.
If the sensor is interferometer based, the sensor comprises a mirror element which is for example arranged on the secondary intermediate frame 45b, a source for an optical beam and a receiver which is adapted to receive the beam from the mirror element. The source for the optical beam is arranged such that the optical beam strikes the mirror element on the secondary intermediate frame 45b. Alternatively, the mirror element may for example be arranged on the sensor frame 40.
The secondary intermediate frame actuator 65 is adapted to move the secondary intermediate frame 45b relative to the sensor frame 40. Optionally, the secondary intermediate frame actuator 65 is integrated into the secondary intermediate frame support 63, which makes that the secondary intermediate frame support 63 is turned into an active support. The addition of the actuator makes that the secondary intermediate frame support is adapted to move the secondary intermediate frame 45b relative to the sensor frame 40 (and relative to the base frame 10), which allows to actively control the position of the secondary intermediate frame 45b relative to the sensor frame 40. This allows an increased positioning accuracy of the optical element 21, and therewith an improvement of the projection accuracy and a reduction of the overlay. In addition, in some embodiments, the level of the requirements for the position measurement system of the wafer stage 60 can be reduced, e.g. with respect to the required range of measurement. The secondary intermediate frame actuator 65 is for example an electromagnetic actuator such as a Lorentz actuator or a reluctance actuator.
The secondary intermediate frame actuator control device 72 of the secondary intermediate frame control system 70 is adapted to receive the measurement data from the secondary intermediate frame position sensor 71 and to control the secondary intermediate frame actuator 65 based on the received measurement data.
Optionally, the lithographic apparatus according to
In the embodiment of
The illuminator frame 81 is separate from the sensor frame 40 of the projection system 20. The illuminator frame support 82 is adapted to connect the illuminator frame 81 to the base frame 10. The illuminator frame support 82 is separate from the force frame support and from the intermediate frame support 46. Optionally, the base frame 10 comprises a primary base frame section and a secondary base frame section, and the illuminator frame support 82 is arranged on the primary base frame section and the intermediate frame support 46 is arranged on the secondary base frame section.
In the embodiment of
Optionally, in the embodiment of
The illuminator frame position sensor 86 is adapted to generate measurement data relating to the position of the illuminator frame 81 relative to the sensor frame 40. The illuminator frame position sensor 86 can for example comprise an interferometric device, an encoder-based device (comprising e.g. a linear encoder) or a capacitive sensor.
The illuminator frame position sensor 86 optionally comprises a sensor sender/receiver element and a sensor target element. If the illuminator frame position sensor 86 is an encoder based device, the sensor optionally comprises a grating, e.g. a one dimensional or two dimensional grating, which is for example arranged on the illuminator frame 81 and an encoder head, which comprises a beam source and at least one receiver element which is adapted to receive the beam from the grating, which encoder head is for example arranged on the sensor frame 40. Alternatively, the grating may be arranged on the sensor frame 40 and the encoder head may be arranged on the illuminator frame 81.
If the sensor is interferometer based, the sensor comprises a mirror element which is for example arranged on the illuminator frame 81, a source for an optical beam and a receiver which is adapted to receive the beam from the mirror element. The source for the optical beam is arranged such that the optical beam strikes the mirror element on the illuminator frame 81. Alternatively, the mirror element may for example be arranged on the sensor frame 40.
The illuminator frame actuator 84 is adapted to move the illuminator frame 81 relative to the sensor frame 40. Optionally, the illuminator frame actuator 84 is integrated into the illuminator frame support 82, which makes that the illuminator frame support 82 is turned into an active support. The addition of the actuator makes that the illuminator frame support is adapted to move the illuminator frame 81 relative to the sensor frame 40 (and relative to the base frame 10), which allows to actively control the position of the illuminator frame 81 relative to the sensor frame 40. The illuminator frame actuator 84 is for example an electromagnetic actuator such as a Lorentz actuator or a reluctance actuator.
The illuminator frame actuator control device 87 of the illuminator frame control system 85 is adapted to receive the measurement data from the illuminator frame position sensor 86 and to control the illuminator frame actuator 84 based on the received measurement data.
Optionally, in the embodiment of
The wafer stage measurement frame position sensor 91 is adapted to generate measurement data relating to the position of the wafer stage measurement frame 61 relative to the sensor frame 40. The wafer stage measurement frame position sensor 91 can for example comprise an interferometric device, an encoder-based device (comprising e.g. a linear encoder) or a capacitive sensor.
The wafer stage measurement frame position sensor 91 optionally comprises a sensor sender/receiver element and a sensor target element. If the wafer stage measurement frame position sensor 91 is an encoder based device, the sensor optionally comprises a grating, e.g. a one dimensional or two dimensional grating, which is for example arranged on the wafer stage measurement frame 61 and an encoder head, which comprises a beam source and at least one receiver element which is adapted to receive the beam from the grating, which encoder head is for example arranged on the sensor frame 40. Alternatively, the grating may be arranged on the sensor frame 40 and the encoder head may be arranged on the wafer stage measurement frame 61.
If the sensor is interferometer based, the sensor comprises a mirror element which is for example arranged on the wafer stage measurement frame 61, a source for an optical beam and a receiver which is adapted to receive the beam from the mirror element. The source for the optical beam is arranged such that the optical beam strikes the mirror element on the wafer stage measurement frame 61. Alternatively, the mirror element may for example be arranged on the sensor frame 40.
The wafer stage measurement frame actuator 93 is adapted to move the wafer stage measurement frame 61 relative to the sensor frame 40. The wafer stage measurement frame actuator 93 is for example an electromagnetic actuator such as a Lorentz actuator or a reluctance actuator.
The wafer stage measurement frame actuator control device 92 of the wafer stage measurement frame control system 90 is adapted to receive the measurement data from the wafer stage measurement frame position sensor 91 and to control the wafer stage measurement frame actuator 93 based on the received measurement data.
Alternatively or in addition, the measurement signal generated by the wafer stage measurement frame position sensor 91 is used to calculate the position of the wafer stage 60 relative to the sensor frame 40. The measurement signal can be used to actively control the position of the wafer stage measurement frame 60, or a part of a wafer stage position measurement arrangement.
The wafer stage measurement control system 90 can also be applied in the embodiments of
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.
Although specific reference may have been made above to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention may be used in other applications, for example imprint lithography, and where the context allows, is not limited to optical lithography. In imprint lithography a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device may be pressed into a layer of resist supplied to the substrate whereupon the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is moved out of the resist leaving a pattern in it after the resist is cured.
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) and extreme ultra-violet (EUV) radiation (e.g. having a wavelength in the range of 5-20 nm), as well as particle beams, such as ion beams or electron beams.
The term “lens”, where the context allows, may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic 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, 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 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16180675.7 | Jul 2016 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/064738 | 6/16/2017 | WO | 00 |
