Lithography method for enhancing illuminator transmission

Abstract

Systems, apparatus, and methods are provided for adjusting illumination slit uniformity in a lithography apparatus. An exemplary method may include determining whether an exposure field for a wafer exposure operation is smaller than a maximum exposure field of a uniformity correction system. In response to determining that the exposure field is smaller than the maximum exposure field, the exemplary method may include modifying illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. The exemplary method may then include determining an optimal position of a finger assembly of the uniformity correction system based on the modified illumination slit uniformity calibration data.

Description

Technical Field

[0001] (Cross - reference to related applications)

[0001] This application claims the priority of U.S. Provisional Patent Application No. 63 / 232,783, filed on August 13, 2021. This application is hereby incorporated by reference in its entirety.

[0002]

[0002] This disclosure relates to systems and methods for correcting illumination non - uniformity in lithography apparatuses and systems.

Background Art

[0003]

[0003] A lithography apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, also interchangeably called a mask or reticle, can be used to generate the circuit patterns to be formed on individual layers of the IC. This pattern can be transferred onto a target portion (e.g., including a part of one or several dies) on a substrate (e.g., a silicon wafer). The transfer of the pattern is typically performed by imaging onto a layer of radiation - sensitive material (e.g., resist) provided on the substrate. Generally, one substrate includes a network of adjacent target portions to which patterns are sequentially applied. Conventional lithography apparatuses include so - called steppers, in which each target portion is irradiated by exposing the entire pattern onto the target portion in one go, and scanners, in which the pattern is scanned with a radiation beam in a given direction (the "scan" direction) while the substrate is scanned synchronously in a direction parallel or antiparallel (i.e., opposite) to a given direction (the "scan" direction), so that each target portion is irradiated. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0004]

[0004] As semiconductor manufacturing processes continue to advance, the dimensions of circuit elements have continuously decreased, while the amount of functional elements such as transistors per device has steadily increased over several decades, following a trend commonly known as "Moore's Law." To keep up with Moore's Law, the semiconductor industry is pursuing technologies that enable the creation of increasingly smaller features. To project patterns onto a substrate, lithography equipment can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the feature that can be patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm.

[0005]

[0005] For example, extreme ultraviolet ("EUV") radiation, such as electromagnetic radiation with wavelengths of about 50 nm or less, including light with a wavelength of about 13.5 nanometers (nm), (sometimes also called soft X-rays), can be used in or with a photolithography apparatus to create extremely small features in or on a substrate, such as a silicon wafer. A lithography apparatus using EUV radiation with wavelengths in the range of 4 nm to 20 nm, for example, 6.7 nm or 13.5 nm, can form smaller features on a substrate than a lithography apparatus using radiation with a wavelength of, for example, 193 nm.

[0006]

[0006] Methods for generating EUV light include, but are not limited to, converting a material having elements such as xenon (Xe), lithium (Li), or tin (Sn) and having emission lines in the EUV range into a plasma state. For example, in one such method called laser-generated plasma (LPP), the plasma can be generated by irradiating a target material, in the form of, for example, droplets, plates, tapes, streams, or clusters of the material, which is interchangeable with fuel in relation to the LPP source, with an amplified light beam, which may be called a drive laser. In this process, the plasma is typically generated in a sealed container, such as a vacuum chamber, and monitored using various types of measuring instruments.

[0007]

[0007] A lithography apparatus typically includes an illumination system that modulates the radiation generated by a radiation source before it enters the patterning device. The illumination system can modify one or more properties of the radiation, such as polarization and / or illumination mode. The illumination system may include a uniformity correction system that corrects or reduces non-uniformity present in the radiation (e.g., intensity non-uniformity). The uniformity correction device can use an actuated finger assembly inserted into the edge of the radiation beam to correct for intensity variations. The spatial width of illumination that can be adjusted by the uniformity correction system depends, among other things, on the size of the finger assembly and the size of the actuated device used to move the finger assembly in the uniformity correction system. Changing the finger parameters from a known working design is not a straightforward process, as it can cause undesirable changes in one or more properties of the radiation beam.

[0008]

[0008] To achieve image quality tolerances on the patterning device and substrate, a controlled uniformity illumination beam is desirable. It is common for the illumination beam to have an uneven intensity profile before it is reflected by or transmitted through the patterning device. At various stages of the lithography process, it is desirable to control the illumination beam to achieve improved uniformity. Uniformity can refer to a constant intensity in the relevant cross-section of the illumination beam, but it can also refer to the ability to control the illumination to achieve selected uniformity parameters. The patterning device imparts a pattern to the radiating beam, which is then projected onto the substrate. The image quality of this projected beam is affected by the uniformity of the beam. [Overview of the Initiative]

[0009]

[0009] Therefore, in order to maximize production capacity and yield rate, minimize manufacturing defects and reduce the cost per device, it is desirable to control illumination uniformity so that the lithography tool performs the lithography process as efficiently as possible.

[0010]

[0010] This disclosure describes various aspects of systems, apparatus, and methods for adjusting the uniformity of illumination slits in a lithography apparatus.

[0011]

[0011] In some embodiments, the Disclosure describes a system. The system may include a uniformity correction system and a controller, which include a plurality of finger assemblies. The plurality of finger assemblies may define the maximum exposure field of the uniformity correction system. A subset of the plurality of finger assemblies may define the exposure field for wafer exposure operations. The controller may be configured to determine whether the exposure field is smaller than the maximum exposure field. In response to the determination that the exposure field is smaller than the maximum exposure field, the controller may further be configured to modify the illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. The controller may then be configured to determine the optimal position of a finger assembly within the subset of the plurality of finger assemblies based on the modified illumination slit uniformity calibration data.

[0012]

[0012] In some embodiments, the maximum exposure field may correspond to the maximum illumination slit width of the uniformity correction system, and the exposure field may correspond to an illumination slit width smaller than the maximum illumination slit width. In some embodiments, the maximum exposure field may correspond to the entire field of the uniformity correction system, and the exposure field may correspond to a portion of the uniformity correction system (e.g., half of the shifted field or half of the potentially shifted field).

[0013]

[0013] In some embodiments, the uniformity correction system may further include a motion control system, which may be coupled to the finger assembly and configured to adjust the optimal position of the finger assembly. In some embodiments, the controller may further be configured to determine changes in the shape of the finger assembly.

[0014]

[0014] In one example, the controller may be configured to determine a change in the position of the optical edge of the fingertip based on the elongation of the fingertip in response to the fingertip being exposed to deep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiation, and to determine a change in the shape of the finger assembly based on the determined change in the position of the optical edge of the fingertip of the finger assembly.

[0015]

[0015] In another example, the controller may be configured to measure changes in the position of a reference mark placed on the finger assembly and to determine changes in the shape of the finger assembly based on the measured changes in the position of the reference mark.

[0016]

[0016] In some embodiments, the controller may be further configured to generate and transmit a control signal to the motion control system, which is configured to instruct the motion control system to adjust the optimal position of the finger assembly based on modified illumination slit uniformity calibration data and determined changes in the shape of the finger assembly.

[0017]

[0017] In some embodiments, the present disclosure describes an apparatus. The apparatus may include a controller configured to determine whether the exposure field for a wafer exposure operation is smaller than the maximum exposure field of a uniformity correction system. In response to the determination that the exposure field is smaller than the maximum exposure field, the controller may further be configured to modify the illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. The controller may then be configured to determine the optimal position of the finger assembly of the uniformity correction system based on the modified illumination slit uniformity calibration data.

[0018]

[0018] In some embodiments, the uniformity correction system may include a plurality of finger assemblies. In some embodiments, the maximum exposure field may be defined by the plurality of finger assemblies, and the exposure field may be defined by a subset of the plurality of finger assemblies. In some embodiments, the subset of the plurality of finger assemblies includes the above-mentioned finger assemblies.

[0019]

[0019] In some embodiments, the maximum exposure field may correspond to the maximum illumination slit width of the uniformity correction system, and the exposure field may correspond to an illumination slit width smaller than the maximum illumination slit width. In some embodiments, the maximum exposure field may correspond to the entire field of the uniformity correction system, and the exposure field may correspond to a portion of the field of the uniformity correction system.

[0020]

[0020] In some embodiments, the controller may be further configured to determine changes in the shape of the finger assembly.

[0021]

[0021] In one example, the controller may be configured to determine a change in the position of the optical edge of the fingertip based on the elongation of the fingertip in response to the fingertip of the finger assembly being exposed to DUV or EUV radiation, and to determine a change in the shape of the finger assembly based on the determined change in the position of the optical edge of the fingertip of the finger assembly.

[0022]

[0022] In another example, the controller may be configured to measure changes in the position of a reference mark placed on the finger assembly and to determine changes in the shape of the finger assembly based on the measured changes in the position of the reference mark.

[0023]

[0023] In some embodiments, the controller may be configured to generate and transmit a control signal to a motion control system coupled to the finger assembly, which is configured to instruct the motion control system to adjust the optimal position of the finger assembly based on modified illumination slit uniformity calibration data and determined changes in the shape of the finger assembly.

[0024]

[0024] In some embodiments, the present disclosure describes a method for adjusting illumination slit uniformity in a lithography apparatus. The method may include a controller determining whether the exposure field for a wafer exposure operation is smaller than the maximum exposure field of a uniformity correction system. In response to the determination that the exposure field is smaller than the maximum exposure field, the method may further include the controller modifying illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. The method may then include the controller determining the optimal position of the finger assembly of the uniformity correction system based on the modified illumination slit uniformity calibration data.

[0025]

[0025] In some embodiments, the uniformity correction system may include a plurality of finger assemblies. In some embodiments, the maximum exposure field may be defined by the plurality of finger assemblies, and the exposure field may be defined by a subset of the plurality of finger assemblies. In some embodiments, the subset of the plurality of finger assemblies includes the above-mentioned finger assemblies.

[0026]

[0026] In some embodiments, the maximum exposure field may correspond to the maximum illumination slit width of the uniformity correction system, and the exposure field may correspond to an illumination slit width smaller than the maximum illumination slit width. In some embodiments, the maximum exposure field may correspond to the entire field of the uniformity correction system, and the exposure field may correspond to a portion of the field of the uniformity correction system.

[0027]

[0027] In some embodiments, the method may further include determining, by a controller, a change in the shape of the finger assembly. In one example, determining a change in the shape of the finger assembly may include determining, by the controller, a change in the position of the optical edge of the finger tip based on an extension of the finger tip in response to the finger tip of the finger assembly being exposed to DUV radiation or EUV radiation, and determining, by the controller, a change in the shape of the finger assembly based on the determined change in the position of the optical edge of the finger tip of the finger assembly.

[0028]

[0028] In another example, determining a change in the shape of the finger assembly may include measuring, by a controller, a change in the position of a reference mark disposed on the finger assembly, and determining, by the controller, a change in the shape of the finger assembly based on the measured change in the position of the reference mark.

[0029]

[0029] In some embodiments, the method may further include generating, by a controller, a control signal configured to command a motion control system coupled to the finger assembly to adjust an optimal position of the finger assembly based on the changed illumination slit uniformity calibration data and the determined change in the shape of the finger assembly, and transmitting, by the controller, the control signal to the motion control system.

[0030]

[0030] Further features as well as the structure and operation of various embodiments are described in detail below with reference to the accompanying drawings. Note that the present disclosure is not limited to the specific embodiments described herein. Such embodiments are shown herein for illustrative purposes only. Further embodiments will be apparent to those skilled in the art based on the teachings contained herein.

Brief Description of the Drawings

[0031]

[0031] The accompanying drawings incorporated herein and forming part thereof illustrate and describe the present invention, and further illustrate the principles of the embodiments of the present disclosure, enabling those skilled in the art to create and use embodiments of the present disclosure.

[0032] [Figure 1A]

[0032] This is a schematic diagram of an exemplary reflective lithography apparatus according to some aspect or part thereof of the present disclosure. [Figure 1B]

[0033] This is a schematic diagram of an exemplary transmission lithography apparatus according to some aspects or parts thereof of the present disclosure. [Figure 2]

[0034] This is a more detailed schematic diagram of the reflective lithography apparatus shown in Figure 1A, according to some aspects or parts thereof of this disclosure. [Figure 3]

[0035] This is a schematic diagram of an exemplary lithography cell according to some aspect or part thereof of the present disclosure. [Figure 4]

[0036] This is a schematic diagram of an exemplary radiation source for an exemplary reflective lithography apparatus, according to some aspects or parts thereof of the present disclosure. [Figure 5A]

[0037] This is a schematic diagram of an exemplary illumination uniformity correction system according to some aspects or parts thereof of the present disclosure. [Figure 5B]

[0037] This is a schematic diagram of an exemplary illumination uniformity correction system according to some aspects or parts thereof of the present disclosure. [Figure 6]

[0038] This is an exemplary graph showing exemplary illumination slit uniformity calibration data for the maximum exposure field, in accordance with some aspects or parts thereof of this disclosure. [Figure 7]

[0039] This is an exemplary graph showing exemplary modified illumination slit uniformity calibration data for a partially exposed field, in accordance with some aspect or part thereof of this disclosure. [Figure 8]

[0040] This is an exemplary method for adjusting the uniformity of the illumination slit in a lithography apparatus, according to some aspects or parts thereof of the present disclosure. [Figure 9]

[0041] An exemplary computer system for implementing some aspects or parts thereof of this disclosure.

[0033]

[0042] The features and advantages of the present invention will become more apparent from the detailed description below, when interpreted in conjunction with the drawings. In the drawings, unless otherwise indicated, similar reference numerals generally indicate elements that are identical, functionally similar, and / or structurally similar. Furthermore, generally, the leftmost digit of the reference numeral identifies the drawing in which the reference numeral first appears. Unless otherwise indicated, the drawings provided through this disclosure should not be interpreted as to scale drawings. [Modes for carrying out the invention]

[0034]

[0043] This specification discloses one or more embodiments incorporating features of the present disclosure. The disclosed embodiments serve only to illustrate the present disclosure. The scope of the present disclosure is not limited to the disclosed embodiments. The breadth and scope of the present disclosure are defined by the claims and equivalents thereof appended to this specification.

[0035]

[0044] Where one or more embodiments are described herein, and where “one embodiment,” “a particular embodiment,” “exemplary embodiment,” etc. are used herein, it is understood that the described embodiments may include certain features, structures, or characteristics, but each embodiment may not necessarily include those features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, where certain features, structures, or characteristics are described in relation to a particular embodiment, it is understood that performing such features, structures, or characteristics in relation to other embodiments, whether expressly described or not, is within the knowledge of those skilled in the art.

[0036]

[0045] Spatially relative terms such as "beneath," "below," "lower," "above," "on," and "upper" may be used herein to facilitate the description of the relationship between one element or function and one or more other elements or functions, as shown in the figures. Spatially relative terms are intended to encompass various orientations of the device in use or operation, in addition to the orientation shown in the figures. The device may be oriented in other ways (it may be rotated 90 degrees or in other directions), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0037]

[0046] As used herein, the term "approximately" indicates a value of a given quantity that may vary based on a particular technique. Based on a particular technique, the term "approximately" may indicate a value of a given quantity that varies within a range of, for example, 10 to 30% of its value (e.g., ±10%, ±20%, or ±30% of its value).

[0038]

[0047] Overview

[0048] An exemplary illumination uniformity correction system called "Unicom" can adjust slit uniformity in the cross-scan direction and attenuate illumination "hot spots" by introducing a finger assembly or set of "finger" into the illumination slit. Unicom can be configured to operate in one of two "modes": (1) a "first mode" that relates to wafer-by-wafer uniformity correction to compensate for illumination effects, and (2) a second mode that modifies slit uniformity on a die-by-die basis to compensate for wafer and process effects, with uniformity correction changing in parallel with die stepping.

[0039]

[0049] When incoming light (e.g., DUV or EUV radiation) heats the unicom fingertip, the unmeasured distance of the fingertip from the unicom position measurement changes, potentially leading to slit uniformity drift. For example, as power increases in the lithography apparatus, the expected critical dimension (CD) impact of uniformity drift can increase from approximately 0.06 nm (<600 W source power) to approximately 0.1 nm (≥600 W source power) or more. The CD impact may be equal to approximately 0.3 times the percentage of uniformity. CD uniformity (CDU) requirements may range from approximately 0.7 nm to approximately 1.2 nm. In some cases, slit uniformity drift may not be compensated for.

[0040]

[0050] In one example, illumination slit uniformity correction can be performed by the Unicom module described in U.S. Patent No. 8,629,973, entitled “LITHOGRAPHIC APPARATUS AND METHOD FOR ILLUMINATION UNIFORMITY CORRECTION AND UNIFORMITY DRIFT COMPENSATION,” issued on January 14, 2014. This patent is included in its entirety by reference. During calibration, the position of each optical block “finger” is determined based on the total illumination slit width (e.g., 26 mm on a wafer scale). The Uniformity Refresh (UR) function provides post-calibration drift protection on a per-lot, and optionally per-wafer basis. However, for small fields (e.g., exposure field widths less than 26 mm), UR may not provide optimal compensation to minimize Unicom transmission loss in all cases.

[0041]

[0051] In contrast, some aspects of this disclosure can provide a state-of-the-art small-field UR function that, in addition to minimizing transmission loss, provides slit uniformity correction in the presence of drift. By determining the optimization target based only on data within the field width, the optimization result can include transmission benefit. Furthermore, depending on the shape of the slit to be corrected and the position of the small-field image within the slit, a gain can be achieved to varying degrees.

[0042]

[0052] Many exemplary embodiments exist of the systems, apparatus, methods, and computer program products disclosed herein. For example, embodiments of this disclosure enable the reduction of CD drift and CDU impact from Unicom. In another example, embodiments of this disclosure enable the increase of illuminator transmission and throughput. As a result, illuminator transmission can be optimized in substantially all cases (for example, a gain greater than 15% in the exemplary embodiments described with reference to Figure 7).

[0043]

[0053] Before detailing these embodiments, it would be useful to present illustrative environments in which embodiments of the present invention can be implemented.

[0044]

[0054] Exemplary lithography system

[0055] Figures 1A and 1B are schematic diagrams of a lithography apparatus 100 and a lithography apparatus 100', respectively, in which embodiments of the present disclosure may be implemented. As shown in Figures 1A and 1B, the lithography apparatuses 100 and 100' are shown from a viewpoint perpendicular to the XZ plane (e.g., a lateral viewpoint) (e.g., the X-axis points to the right, the Z-axis points upward, and the Y-axis points in the direction from the reader towards the paper), and the patterning device MA and substrate W are shown from an additional viewpoint perpendicular to the XY plane (e.g., an upward viewpoint) (e.g., the X-axis points to the right, the Y-axis points upward, and the Z-axis points in the direction from the paper towards the reader).

[0045]

[0056] In some embodiments, the lithography apparatus 100 and / or lithography apparatus 100' may include one or more of the following structures: an illumination system IL (e.g., an illuminator) configured to adjust a radiation beam B (e.g., a DUV radiation beam or an EUV radiation beam); a support structure MT (e.g., a mask table) configured to support a patterning device MA (e.g., a mask, reticle, or dynamic patterning device) and connected to a first positioner PM configured to precisely position the patterning device MA; and a substrate table such as a substrate table WT (e.g., a wafer table) configured to hold a substrate W (e.g., a resist-coated wafer) and connected to a second positioner PW configured to precisely position the substrate W. The lithography apparatus 100 and 100' may also include a projection system PS (e.g., a refractive projection lens system) configured to project the pattern applied to the radiation beam B by the patterning device MA onto a target portion C of the substrate W (e.g., a portion containing one or more dies). In lithography apparatus 100, the patterning device MA and projection system PS are reflective. In lithography apparatus 100', the patterning device MA and projection system PS are transmissive.

[0046]

[0057] In some embodiments, during operation, the illumination system IL can receive a radiated beam from a radiation source SO (e.g., via a beam delivery system BD shown in Figure 1B). The illumination system IL may include various types of optical structures, such as refractive, reflective, reflex-refracting, magnetic, electromagnetic, electrostatic, and / or other types of optical components, or any combination thereof, for inducing, shaping, or controlling the radiation. In some embodiments, the illumination system IL may be configured to adjust the radiated beam B so that it has a desired spatial and angular intensity distribution within the cross-section of the patterning device MA.

[0047]

[0058] In some embodiments, the support structure MT can hold the patterning device MA in a manner that depends on the orientation of the patterning device MA relative to a reference frame, the design of at least one of the lithography apparatuses 100 and 100', and other conditions such as whether the patterning device MA is held in a vacuum environment. The support structure MT can hold the patterning device MA using mechanical, vacuum, electrostatic, or other clamping techniques. The support structure MT can be, for example, a frame or a table, and can be fixed or movable as needed. By using sensors, the support structure MT can ensure that the patterning device MA is in a desired position relative to, for example, a projection system PS.

[0048]

[0059] The term "patterning device" (MA) should be broadly interpreted to refer to any device that can be used to impart a pattern to the cross-section of a radiation beam B in order to generate a pattern on a target portion C of a substrate W. The pattern imparted to the radiation beam B may correspond to a specific functional layer within the device that is generated on the target portion C to form an integrated circuit.

[0049]

[0060] In some embodiments, the patterning device MA may be transmissive (as in the lithography apparatus 100' in Figure 1B) or reflective (as in the lithography apparatus 100 in Figure 1A). The patterning device MA may include a variety of structures, such as a reticle, a mask, a programmable mirror array, a programmable LCD panel, other suitable structures, or a combination thereof. The mask may include various mask types, such as a binary mask, an alternating phase-shift mask, an attenuated phase-shift mask, and various hybrid mask types. In one example, the programmable mirror array may include a matrix array of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in a different direction. The tilted mirrors can impart a pattern to the radiation beam B reflected by the matrix of small mirrors.

[0050]

[0061] The term “projection system” PS should be interpreted broadly and may encompass any type of projection system, including refractive optical systems, reflective optical systems, reflector-refractor optical systems, magneto-optical systems, anamorphic optical systems, electromagnetic optical systems, and electrostatic optical systems, or any combination thereof, as appropriate in accordance with the exposure radiation used and / or other factors such as the use of immersion liquid (e.g., on a substrate W) or vacuum. A vacuum environment may be used for EUV or electron beam radiation because other gases may absorb too much radiation or electrons. Therefore, a vacuum environment can be provided throughout the beam path using vacuum walls and vacuum pumps. Furthermore, where the term “projection lens” is used herein, in some embodiments it may be considered synonymous with the more general term “projection system” PS.

[0051]

[0062] In some embodiments, the lithography apparatus 100 and / or lithography apparatus 100' may be of a type having two (dual-stage) or more substrate tables WT and / or two or more mask tables. In such a “multi-stage” machine, additional substrate tables WT can be used in parallel, or preparation steps can be performed on one or more other tables while one or more substrate tables WT are being used for exposure. In one example, while a substrate W placed on one of the substrate tables WT is being used to expose a pattern on this substrate W, preparation steps for subsequent exposure can be performed on another substrate W placed on another substrate table WT. In some embodiments, the additional tables may not be substrate tables WT.

[0052]

[0063] In some embodiments, in addition to the substrate table WT, the lithography apparatus 100 and / or lithography apparatus 100' may include a measurement stage. The measurement stage may be positioned to hold sensors. The sensors may be positioned to measure the characteristics of the projection system PS, the characteristics of the radiation beam B, or both. In some embodiments, the measurement stage may hold multiple sensors. In some embodiments, if the substrate table WT is away from the projection system PS, the measurement stage may move below the projection system PS.

[0053]

[0064] In some embodiments, the lithography apparatus 100 and / or lithography apparatus 100' may be of a type that can cover at least a portion of the substrate with a liquid having a relatively high refractive index, such as water, to fill the space between the projection system PS and the substrate W. The immersion liquid may also be applied to other spaces within the lithography apparatus, such as between the patterning device MA and the projection system PS. The immersion technique allows for a larger numerical aperture of the projection system. As used herein, the term "immersion" does not mean that the substrate or other structure must be submerged in the liquid, but merely means that a liquid is placed between the projection system and the substrate during exposure. Various immersion techniques are described in U.S. Patent No. 6,952,253, entitled "LITHOGRAPHIC APPARATUS AND DEVICE MANUFACTURING METHOD," issued on 4 October 2005, which is included in its entirety by reference.

[0054]

[0065] Referring to Figures 1A and 1B, the illumination system IL receives the radiated beam B from the radiated source SO. For example, if the radiated source SO is an excimer laser, the radiated source SO and the lithography apparatus 100 or 100' can be separate physical entities. In such a case, the radiated source SO is not considered to form part of the lithography apparatus 100 or 100', and the radiated beam B is delivered from the radiated source SO to the illumination system IL using a beam delivery system BD (e.g., shown in Figure 1B) which includes, for example, appropriate guide mirrors and / or beam expanders. In other cases, for example, if the radiated source SO is a mercury lamp, the radiated source SO may be an integral part of the lithography apparatus 100 or 100'. The radiated source SO and the illuminator IL, together with the beam delivery system BD as needed, can be called a radiated system.

[0055]

[0066] In some embodiments, the illumination system IL may include an adjuster AD for adjusting the angular intensity distribution of the radiated beam. Typically, at least the outer radius range and / or inner radius range (generally referred to as "σ-outer" and "σ-inner," respectively) of the intensity distribution within the pupil plane of the illuminator can be adjusted. Furthermore, the illumination system IL may include various other components such as an integrator IN and a radiated collector CO (e.g., a capacitor or collector optical system). In some embodiments, the illumination system IL can be used to adjust the radiated beam B to have desired uniformity and intensity distribution in cross-section.

[0056]

[0067] Referring to Figure 1A, during operation, the radiant beam B is incident on a patterning device MA (e.g., a mask, reticle, programmable mirror array, programmable LCD panel, any other suitable structure, or a combination thereof) which can be held on a support structure MT (e.g., a mask table), and a pattern (e.g., a design layout) present on the patterning device MA can be formed. In the lithography apparatus 100, the radiant beam B can be reflected from the patterning device MA. The radiant beam B that has crossed the patterning device MA (e.g., after being reflected from the patterning device MA) passes through a projection system PS, which can focus the radiant beam B onto a target portion C on the substrate W or onto a sensor placed on the stage.

[0057]

[0068] In some embodiments, a second positioner PW and a position sensor IFD2 (e.g., an interference device, a linear encoder, or a capacitance sensor) can be used to precisely move the substrate table WT to position various target portions C along the path of the radiated beam B, for example. Similarly, a first positioner PM and another position sensor IFD1 (e.g., an interference device, a linear encoder, or a capacitance sensor) can be used to precisely position the patterning device MA along the path of the radiated beam B.

[0058]

[0069] In some embodiments, the patterning device MA and the substrate W can be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2. Figures 1A and 1B show substrate alignment marks P1 and P2 occupying dedicated target portions, although substrate alignment marks P1 and P2 may be positioned in the space between target portions. When substrate alignment marks P1 and P2 are positioned between target portions C, they are known as scribe line alignment marks. Alternatively, substrate alignment marks P1 and P2 can be placed within the area of ​​target portion C as in-die marks. These in-die marks can also be used, for example, as metrologic marks for overlay measurements.

[0059]

[0070] In some embodiments, for illustrative purposes only and not limiting, one or more of the drawings herein may utilize a Cartesian coordinate system. A Cartesian coordinate system includes three axes: the X, Y, and Z axes. Each of the three axes is orthogonal to the other two axes (for example, the X axis is perpendicular to the Y and Z axes, the Y axis is perpendicular to the X and Z axes, and the Z axis is perpendicular to the X and Y axes). A rotation about the X axis is denoted as an Rx rotation. A rotation about the Y axis is denoted as a Ry rotation. A rotation about the Z axis is denoted as an Rz rotation. In some embodiments, the X and Y axes define the horizontal plane, and the Z axis is perpendicular. In some embodiments, the Cartesian coordinate system may be oriented differently, for example, such that the Z axis has a component along the horizontal plane. In some embodiments, another coordinate system, such as a cylindrical coordinate system, may be used.

[0060]

[0071] Referring to Figure 1B, the radiation beam B is incident on a patterning device MA held on a support structure MT, and a pattern is formed by the patterning device. After crossing the patterning device MA, the radiation beam B passes through a projection system PS, which focuses the beam onto a target portion C of the substrate W. In some embodiments, the projection system PS may have a pupil conjugate to the pupil of the illumination system. In some embodiments, a portion of the radiation originates from the intensity distribution in the pupil of the illumination system, crosses the mask pattern MP without being affected by diffraction, and generates an image of the intensity distribution in the pupil of the illumination system.

[0061]

[0072] The projection system PS projects an image MP' of the mask pattern MP onto a resist layer coated on the substrate W. The image MP' is formed by a diffracted beam generated from the mask pattern MP by radiation from the intensity distribution. For example, the mask pattern MP may include an array of lines and space. Diffraction of radiation different from zero-order diffraction in the array generates a diffracted beam whose direction is changed perpendicular to the lines. The reflected light (e.g., the zero-order diffracted beam) traverses the pattern without changing its propagation direction. The zero-order diffracted beam reaches the pupil conjugate of the projection system PS upstream of the pupil conjugate, traversing the upper lens or upper lens group of the projection system PS. The portion of the intensity distribution related to the zero-order diffracted beam in the plane of the pupil conjugate is an image of the intensity distribution in the pupil of the illumination system IL. In some embodiments, an aperture device can be positioned on or substantially on the plane containing the pupil conjugate of the projection system PS.

[0062]

[0073] The projection system PS is arranged by lenses or lens groups to capture not only the zero-order diffracted beam but also the primary diffracted beam or primary and higher-order diffracted beams (not shown). In some embodiments, the resolution-enhancing effect of dipole illumination can be utilized by using dipole illumination to image a line pattern extending perpendicular to the line. For example, the primary diffracted beam interferes with the corresponding zero-order diffracted beam at the level of the substrate W to produce an image of the mask pattern MP with the highest possible resolution and process window (e.g., usable depth of field combined with an acceptable exposure dose deviation). In some embodiments, astigmatism can be reduced by providing radiating poles (not shown) in opposing quadrants of the illumination system pupil. Furthermore, in some embodiments, astigmatism can be reduced by blocking the zero-order beam in the pupil conjugate of the projection system PS related to the radiating poles of the opposing quadrants. This is described in more detail in U.S. Patent No. 7,511,799, entitled "LITHOGRAPHIC PROJECTION APPARATUS AND A DEVICE MANUFACTURING METHOD," issued on March 31, 2009. This is included in its entirety by reference.

[0063]

[0074] In some embodiments, a second positioner PW and a position measuring system PMS (including, for example, position sensors such as an interference device, a linear encoder, or a capacitance sensor) can be used to precisely move the substrate table WT to position various target portions C at focused and aligned positions within the path of the radiation beam B. Similarly, a first positioner PM and another position sensor (e.g., an interference device, a linear encoder, or a capacitance sensor) (not shown in Figure 1B) can be used to precisely position the patterning device MA relative to the path of the radiation beam B (for example, after mechanical removal from the mask library or during scanning). The patterning device MA and the substrate W can be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2.

[0064]

[0075] Generally, the movement of the support structure MT can be achieved using long-stroke positioners (coarse positioning) and short-stroke positioners (fine positioning) that form part of the first positioner PM. Similarly, the movement of the substrate table WT can be achieved using long-stroke positioners and short-stroke positioners that form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the support structure MT can be connected to or fixed only to short-stroke actuators. The patterning device MA and the substrate W can be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2. The substrate alignment marks (as shown in the figure) occupy dedicated target areas, but they may also be positioned in the space between target areas (e.g., scribe line alignment marks). Similarly, in situations where multiple dies are provided on the patterning device MA, the mask alignment marks M1 and M2 may be positioned between those dies.

[0065]

[0076] The support structure MT and patterning device MA may be placed inside the vacuum chamber V. In this case, an in-vacuum robot can be used to move the patterning device, such as a mask, inside and outside the vacuum chamber. Alternatively, if the support structure MT and patterning device MA are outside the vacuum chamber, an out-of-vacuum robot can be used for various transport operations, similar to an in-vacuum robot. In some embodiments, both the in-vacuum and out-of-vacuum robots need to be calibrated to smoothly move any payload (e.g., a mask) to a fixed kinematic mount on a transfer station.

[0066]

[0077] In some embodiments, the lithography apparatuses 100 and 100' can be used in at least one of the following modes:

[0067]

[0078] 1. In step mode, the support structure MT and substrate table WT are kept essentially stationary, while the entire pattern applied to the radiation beam B is projected onto the target portion C in a single pass (i.e., single static exposure). Next, the substrate table WT is moved in the X and / or Y directions so that another target portion C can be exposed.

[0068]

[0079] 2. In scan mode, the support structure MT and substrate table WT are scanned synchronously, while the pattern applied to the radiation beam B is projected onto the target portion C (i.e., single dynamic exposure). The speed and direction of the substrate table WT relative to the support structure MT (e.g., mask table) can be determined by the magnification (reduction) and image inversion characteristics of the projection system PS.

[0069]

[0080] 3. In another mode, the support structure MT is kept essentially stationary, holding the programmable patterning device MA, and projects the pattern applied to the radiation beam B onto the target portion C while the substrate table WT is moved or scanned. A pulsed radiation source SO can be used. The programmable patterning device is updated as needed each time the substrate table WT is moved, or between consecutive radiation pulses during scanning. This operating mode is readily available for maskless lithography using a programmable patterning device MA such as a programmable mirror array.

[0070]

[0081] In some embodiments, the lithography apparatuses 100 and 100' can utilize combinations and / or variations of the above-described modes of use, or entirely different modes of use.

[0071]

[0082] In some embodiments, as shown in Figure 1A, the lithography apparatus 100 may include an EUV radiation source configured to generate an EUV radiation beam B for EUV lithography. Generally, the EUV radiation source can be configured within a radiation source SO, and the corresponding illumination system IL can be configured to regulate the EUV radiation beam B of the EUV radiation source.

[0072]

[0083] Figure 2 shows a lithography apparatus 100 in more detail, including the radiation source SO (e.g., source collector), illumination system IL, and projection system PS. As shown in Figure 2, the lithography apparatus 100 is illustrated from a viewpoint perpendicular to the XZ plane (e.g., a lateral viewpoint) (e.g., the X-axis points to the right and the Z-axis points upward).

[0073]

[0084] The radiation source SO is constructed and positioned to maintain a vacuum environment within a closed structure 220. The radiation source SO includes a source chamber 211 and a collector chamber 212 and is configured to generate and transmit EUV radiation. To generate EUV radiation, an EUV radiation-emitting plasma 210 can be generated by a gas or vapor such as xenon (Xe) gas, lithium (Li) vapor, or tin (Sn) vapor, causing it to emit radiation in the EUV range of the electromagnetic spectrum. At least partially ionized EUV radiation-emitting plasma 210 can be generated by, for example, a discharge or a laser beam. For efficient radiation generation, for example, Xe gas, Li vapor, Sn vapor, or any other suitable gas or vapor with a partial pressure of about 10.0 Pascals (Pa) can be used. In some embodiments, an excited tin plasma is supplied to generate EUV radiation.

[0074]

[0085] The radiation emitted by the EUV emission plasma 210 is delivered from the source chamber 211 into the collector chamber 212 via an optional gas barrier or contaminant trap 230 (sometimes also called a contaminant barrier or foil trap) positioned within or behind the opening of the source chamber 211. The contaminant trap 230 may include a channel structure. Alternatively, the contaminant trap 230 may include a gas barrier or a combination of a gas barrier and a channel structure. The contaminant trap 230 further described herein includes at least a channel structure.

[0075]

[0086] The collector chamber 212 may include a radiation collector CO (e.g., a condenser or collector optical system), which may be a so-called grazing-incident collector. The radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation crossing the radiation collector CO can be reflected by the grating spectral filter 240 and focused to a virtual source point IF. The virtual source point IF is generally called an intermediate focus, and the source collector device is arranged such that the virtual source point IF is located in or near the aperture 219 of the closed structure 220. The virtual source point IF is an image of the EUV radiation-emitting plasma 210. Infrared (IR) radiation can be suppressed using the grating spectral filter 240.

[0076]

[0087] Subsequently, the radiation traverses the illumination system IL. The illumination system IL may include a faceted field mirror device 222 and a faceted pupil mirror device 224, which are arranged to give the patterning device MA a desired angular distribution of the radiation beam 221 and a desired uniformity of radiation intensity in the patterning device MA. When the radiation beam 221 is reflected by the patterning device MA held by the support structure MT, a patterned beam 226 is formed, and this patterned beam 226 is imaged by the projection system PS onto a substrate W held by a wafer stage or substrate table WT via reflective elements 228, 229.

[0077]

[0088] In general, the illumination system IL and projection system PS may have more elements than those shown. Optionally, a grating spectral filter 240 may be present depending on the type of lithography apparatus. Furthermore, there may be more mirrors than those shown in Figure 2. For example, the projection system PS may have one to six additional reflective elements compared to those shown in Figure 2.

[0078]

[0089] The CO radiation collector shown in Figure 2 is shown as a nested collector having grazing-incident reflectors 253, 254, and 255, as just one example of a collector (or collector mirror). The grazing-incident reflectors 253, 254, and 255 are arranged axially symmetrically with respect to the optical axis O, and this type of CO radiation collector is preferably used in combination with a discharge-produced plasma (DPP) source.

[0079]

[0090] Exemplary lithography cell

[0091] Figure 3 shows a lithography cell 300, sometimes called a lithocell or cluster. As shown in Figure 3, the lithography cell 300 is shown from a viewpoint perpendicular to the XY plane (e.g., an overhead viewpoint) (for example, the X-axis points to the right and the Y-axis points upward).

[0080]

[0092] A lithography apparatus 100 or 100' may form part of a lithography cell 300. The lithography cell 300 may also include one or more devices that perform pre-exposure and post-exposure processes on the substrate. For example, these devices may include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, a cooling plate CH, and a bake plate BK. A substrate handler RO (e.g., a robot) picks up the substrates from input / output ports I / O1 and I / O2, moves them between various process devices, and delivers them to the loading bay LB of the lithography apparatus 100 and 100'. These devices are often collectively referred to as a track and are under the control of a track control unit TCU. The TCU itself is controlled by a supervisory control system SCS. The SCS also controls the lithography apparatus via a lithography control unit LACU. Thus, these various devices can be operated to maximize throughput and processing efficiency.

[0081]

[0093] Example radiation source

[0094] Figure 4 shows an example of a radiation source SO for an exemplary reflective lithography apparatus (e.g., lithography apparatus 100 in Figure 1A). As shown in Figure 4, the radiation source SO is illustrated from a viewpoint perpendicular to the XY plane (e.g., an overhead viewpoint), as described below.

[0082]

[0095] The radiation source SO shown in Figure 4 is of a type sometimes called a laser-produced plasma (LPP) source. For example, a laser system 401, which may include a carbon dioxide (CO2) laser, is configured to deposit energy via one or more laser beams 402 onto one or more discrete tin (Sn) droplets supplied from, for example, a fuel target generator 403 (e.g., a fuel ejector, droplet generator) to a fuel target 403'. According to several embodiments, the laser system 401 may be or operate in the form of a pulsed wave, continuous wave, or quasi-continuous wave laser. The trajectory of the fuel target 403' (e.g., droplets) emitted from the fuel target generator 403 may be parallel to the X-axis. According to several embodiments, one or more laser beams 402 propagate in a direction parallel to the Y-axis, which is perpendicular to the X-axis. The Z-axis is perpendicular to both the X-axis and the Y-axis and extends generally in a direction toward (or toward) the plane of the paper, although other configurations are used in other embodiments. In some embodiments, one or more laser beams 402 may propagate in directions other than parallel to the Y-axis (for example, in directions other than perpendicular to the X-axis direction of the trajectory of the fuel target 403').

[0083]

[0096] In some embodiments, one or more laser beams 402 may include a pre-pulsed laser beam and a main-pulsed laser beam. In such embodiments, the laser system 401 can be configured to generate a modified fuel target by impacting each of the fuel targets 403' with the pre-pulsed laser beam. The laser system 401 can further be configured to generate a plasma 407 by impacting the modified fuel target with the main-pulsed laser beam.

[0084]

[0097] Although the following description refers to tin, any suitable target material can be used. The target material can be, for example, in liquid form, or, for example, a metal or alloy. The fuel target generator 403 may include a nozzle configured to guide tin (e.g., discrete droplets) in the form of, for example, fuel target 403' along a trajectory toward the plasma-forming region 404. Throughout the remainder of the description, references to “fuel,” “fuel target,” or “fuel droplets” should be understood to refer to the target material (e.g., droplets) emitted by the fuel target generator 403. The fuel target generator 403 may include a fuel discharger. One or more laser beams 402 are incident on the target material (e.g., tin) in the plasma-forming region 404. The deposition of laser energy on the target material generates plasma 407 in the plasma-forming region 404. During the de-excitation and recombination of ions and electrons in the plasma, radiation, including EUV radiation, is emitted from the plasma 407.

[0085]

[0098] EUV radiation is collected and focused by a radiation collector 405 (e.g., radiation collector CO). In some embodiments, the radiation collector 405 may include a near-normal incident radiation collector (sometimes more commonly referred to as a normal incident radiation collector). The radiation collector 405 can be a multilayer structure arranged to reflect EUV radiation (e.g., EUV radiation having a desired wavelength such as about 13.5 nm). According to some embodiments, the radiation collector 405 may have an elliptical configuration with two foci. As discussed herein, the first focal point may be in the plasma-forming region 404, and the second focal point may be in the intermediate focal point 406.

[0086]

[0099] In some embodiments, the laser system 401 can be positioned at a relatively long distance from the radiation source SO. If this is the case, one or more laser beams 402 can be delivered from the laser system 401 to the radiation source SO by a beam delivery system (not shown) including, for example, suitable guide mirrors and / or beam expanders and / or other optical systems. The laser system 401 and the radiation source SO can together be considered a radiation system.

[0087]

[0100] The radiation reflected by the radiation collector 405 forms a radiation beam B. The radiation beam B is focused at a point (e.g., an intermediate focus 406) to form an image of the plasma-forming region 404. This image acts as a virtual radiation source for the illumination system IL. The point at which the radiation beam B is focused can be called the intermediate focus (IF) (e.g., intermediate focus 406). The radiation source SO is positioned such that the intermediate focus 406 is located at or near the aperture 408 of the closed structure 409 of the radiation source SO.

[0088]

[0101] The radiant beam B enters the illumination system IL, which is configured to adjust the radiant beam B, from the radiation source SO. From the illumination system IL, the radiant beam B enters the patterning device MA, which is held by the support structure MT. The patterning device MA reflects the radiant beam B to impart a pattern. After being reflected from the patterning device MA, the patterned radiant beam B enters the projection system PS. The projection system includes multiple mirrors configured to project the radiant beam B onto a substrate W, which is held by the substrate table WT. The projection system PS can form an image of a feature smaller than the corresponding feature on the patterning device MA by applying a reduction factor to the radiant beam. For example, a reduction factor of 4 can be applied. In Figure 2, the projection system PS is illustrated as having two mirrors, but the projection system PS can include any number of mirrors (e.g., six mirrors).

[0089]

[0102] The SO radiation source may include components not shown in Figure 4. For example, a spectral filter can be provided within the SO radiation source. The spectral filter can be substantially transparent to EUV radiation but substantially block radiation of other wavelengths, such as infrared radiation.

[0090]

[0103] The radiation source SO (or radiation system) may further include a fuel target imaging system for obtaining an image of the fuel target (e.g., droplets) in the plasma-forming region 404, or more specifically, an image of the shadow of the fuel target. The fuel target imaging system can detect light diffracted from the edges of the fuel target. Where the image of the fuel target is referred to below, this also refers to the shadow image of the fuel target or the diffraction pattern produced by the fuel target.

[0091]

[0104] The fuel target imaging system may include a photodetector such as a CCD array or CMOS sensor, but it will be acknowledged that any imaging device suitable for acquiring an image of the fuel target can be used. In addition to the photodetector, the fuel target imaging system may include one or more optical components such as lenses. For example, the fuel target imaging system may include a camera 410, such as a combination of a photosensor or photodetector and one or more lenses. The optical components may be selected so that the photosensor, i.e., the camera 410, acquires near-field and / or far-field images. The camera 410 can be positioned at any position within the radiation source SO having a line of sight to one or more markers (not shown in Figure 4) provided on the plasma-forming region 404 and the radiation collector 405. However, in some embodiments, it may be necessary to position the camera 410 away from the propagation paths of one or more laser beams 402 and from the trajectory of the fuel target emitted from the fuel target generator 403 in order to avoid damage to the camera 410. In some embodiments, the camera 410 is configured to provide an image of the fuel target to the controller 411 via connection 412. Although connection 412 is illustrated as a wired connection, it will be acknowledged that connection 412 (and other connections referred to herein) may be implemented as either wired or wireless connections or a combination thereof.

[0092]

[0105] As shown in Figure 4, the radiation source SO may include a fuel target generator 403 configured to generate fuel targets 403' (e.g., discrete tin droplets) and emit them toward a plasma-forming region 404. The radiation source SO may further include a laser system 401 configured to collide one or more laser beams 402 onto one or more of the fuel targets 403' to generate plasma 407 in the plasma-forming region 404. The radiation source SO may further include a radiation collector 405 (e.g., radiation collector CO) configured to collect radiation emitted by the plasma 407.

[0093]

[0106] Exemplary Illumination Uniformity Correction System

[0107] Figures 5A and 5B are schematic diagrams of exemplary illumination uniformity correction systems 500 according to some aspects of the present disclosure.

[0094]

[0108] As shown in Figure 5A, an exemplary illumination uniformity correction system 500 may include a set of finger assemblies 502 (e.g., 28 finger assemblies with a pitch of approximately 4 mm), a set of fingertips 504 (e.g., each finger assembly containing a fingertips), a frame 528, a set of bends 530, and a set of bends 532. In some embodiments, the exemplary illumination uniformity correction system 500 can change the intensity of the illumination slits by individually controlling the position of each finger assembly in the set of finger assemblies 502 (e.g., using a controller 590 and a motion control system including, but not limited to, one or more magnet assemblies) in order to achieve target uniformity. In some embodiments, the optical edges of one or more fingertips in the set of fingertips 504 may be exposed to radiation 580 (e.g., DUV or EUV radiation) during the wafer exposure operation of the lithography apparatus. This may cause one or more fingertips to elongate as a result of exposure (or in the course of multiple exposures).

[0095]

[0109] As shown in Figure 5B, the set of finger assemblies 502 may include a finger assembly 520. The finger assembly 520 may include a finger body 522, a finger tip 524, an actuator 526 (for adjusting the position of the finger assembly 520, for example), a position sensor 529 (including, but not limited to, an encoder scale, for example), a bend 531, and a bend 533. The finger tip 524 may include an optical edge 524a and a mechanical edge 524b. In some embodiments, the optical edge 524a of the finger tip 524 may be exposed to radiation 580 (e.g., DUV or EUV radiation) during the wafer exposure operation of a lithography apparatus. As a result, one or more finger tips 524 may be stretched as a result of exposure (or in the course of multiple exposures).

[0096]

[0110] Referring here to Figures 5A and 5B, in some embodiments, the exemplary illumination uniformity correction system 500 may include a controller 590 configured to determine a change in the shape of one or more finger assemblies within a set of finger assemblies 502.

[0097]

[0111] In some embodiments, a set of finger assemblies 502 can define the maximum exposure field of the uniformity correction system, and a subset of the set of finger assemblies 502 can define the exposure field for wafer exposure operations. The controller 590 can be configured to determine whether the exposure field is smaller than the maximum exposure field. In response to the determination that the exposure field is smaller than the maximum exposure field, the controller 590 can further be configured to modify the illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. The controller 590 can then be configured to determine the optimal position of the finger assembly 520 within the subset of the set of finger assemblies 502 based on the modified illumination slit uniformity calibration data.

[0098]

[0112] In some embodiments, the maximum exposure field corresponds to the maximum illumination slit width of the uniformity correction system, and the exposure field can correspond to an illumination slit width smaller than the maximum illumination slit width. In some embodiments, the maximum exposure field corresponds to the entire field of the uniformity correction system, and the exposure field can correspond to a portion of the uniformity correction system (e.g., half of the shifted field or half of the potentially shifted field).

[0099]

[0113] In some embodiments, the uniformity correction system may further include a motion control system, which may include an actuator 526 coupled to the finger body 522, but is not limited to this system. The motion control system may be coupled to the finger assembly 520 and may be configured to adjust the optimal position of the finger assembly 520. In some embodiments, the controller 590 may further be configured to determine changes in the shape of the finger assembly 520.

[0100]

[0114] In one example, the controller 590 may be configured to determine a change in the position of the optical edge 524a of the finger tip 524 of the finger assembly 520 based on the elongation of the finger tip 524 in response to exposure of the finger tip 524 of the finger assembly 520 to DUV or EUV radiation. The controller 590 may also be configured to determine a change in the shape of the finger assembly 520 based on the determined change in the position of the optical edge 524a of the finger tip 524 of the finger assembly 520.

[0101]

[0115] In another example, the controller 590 may be configured to measure changes in the position of a reference mark placed on the finger assembly 520. The controller 590 may also be configured to determine changes in the shape of the finger assembly 520 based on the measured changes in the position of the reference mark.

[0102]

[0116] In some embodiments, the controller 590 may be further configured to generate a control signal configured to instruct the motion control system to adjust the optimal position of the finger assembly 520 based on modified illumination slit uniformity calibration data and determined changes in the shape of the finger assembly 520. The controller 590 may be further configured to transmit the control signal to the motion control system.

[0103]

[0117] In one non-limiting example for illustrative purposes, the controller 590 may be configured to determine a change in the position of the optical edge 524a of the fingertip 524 of the finger assembly 520 based on the extension of the fingertip 524 in response to the fingertip 524 being exposed to radiation 580. The controller 590 may be configured to generate a control signal configured to change the position of the finger assembly 520 based on the determined change in the shape of the finger assembly 520. The controller 590 may further be configured to transmit the control signal to a motion control system coupled to the finger assembly 520, such as an actuator 526 coupled to the finger body 522.

[0104]

[0118] Figure 6 shows an exemplary graph 600 illustrating exemplary illumination slit uniformity calibration data for a maximum exposure field (e.g., “aperture slit” or “full field”) according to several aspects of this disclosure. As shown in Figure 6, the exemplary graph 600 includes a measured intensity curve 602 for the maximum exposure field and illumination slit uniformity calibration data 604 associated with the maximum exposure field. The illumination slit uniformity calibration data 604 can be used to provide, for example, a unicom correction for the maximum exposure field. However, if only the left side of the reticle (half or a quarter of the field is shifted) is used for exposure, the UR result is still the low level that occurs with the full calibration data (e.g., an arbitrary unit (AU) of 0.95 may be copied as the intensity of the small field UR).

[0105]

[0119] Figure 7 shows an exemplary graph 700 illustrating exemplary modified illumination slit uniformity calibration data for a partially exposed field (e.g., the left half of the field) according to several embodiments of the present disclosure. As shown in Figure 7, the exemplary graph 700 includes a measured intensity curve 702 for the partially exposed field, illumination slit uniformity calibration data 704 related to the maximum exposed field, and modified illumination slit uniformity calibration data 706 related to the partially exposed field. The modified illumination slit uniformity calibration data 706 can be used to provide, for example, a unicom correction for the partially exposed field. In some embodiments, the illumination slit uniformity calibration data 704 sets all image widths to the 0.95 level, and the modified illumination slit uniformity calibration data 706 can set image widths to levels greater than 1.10, depending on the data within each field image width. As a result, illuminator transmission can be optimized in substantially all cases (e.g., a gain of about 17% in this example).

[0106]

[0120] Exemplary process for adjusting the uniformity of lighting slits

[0121] Figure 8 shows an exemplary method 800 for adjusting illumination slit uniformity in a lithography apparatus, according to some aspects or parts thereof of this disclosure. The operations described with reference to exemplary method 800 may be performed by or in accordance with the systems, apparatus, components, techniques, or combinations thereof described herein, including those described above with reference to Figures 1 to 7 and described later with reference to Figure 9.

[0107]

[0122] In operation 802, the method may include a controller (e.g., controller 590) determining whether the exposure field for the wafer exposure operation is smaller than the maximum exposure field of a uniformity correction system (e.g., an exemplary illumination uniformity correction system 500). In some embodiments, the uniformity correction system may include a plurality of finger assemblies (e.g., a set of finger assemblies 502), the maximum exposure field is defined by the plurality of finger assemblies, and the exposure field is defined by a subset of the plurality of finger assemblies (e.g., a subset of the set of finger assemblies 502). In some embodiments, the maximum exposure field may correspond to the maximum illumination slit width of the uniformity correction system, and the exposure field may correspond to an illumination slit width smaller than the maximum illumination slit width. In some embodiments, the maximum exposure field may correspond to the entire field of the uniformity correction system, and the exposure field may correspond to a partial field of the uniformity correction system (e.g., a shifted half field or a potentially shifted half field). In some embodiments, the determination of whether the exposure field is smaller than the maximum exposure field can be achieved by appropriate mechanical or other methods, and may include determining whether the exposure field is smaller than the maximum exposure field according to any embodiment or any combination of the embodiments described above with reference to Figures 1 to 7 and below with reference to Figure 9.

[0108]

[0123] In operation 804, the method may include, in response to a determination by the controller that the exposure field is smaller than the maximum exposure field, modifying the illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. In some embodiments, the modification of the illumination slit uniformity calibration data can be achieved using appropriate mechanical or other methods and may include modifying the illumination slit uniformity calibration data in any embodiment or any combination of the embodiments described above with reference to Figures 1 to 7 and below with reference to Figure 9.

[0109]

[0124] In operation 806, the method may include the controller determining the optimal position of the finger assembly of the uniformity correction system (e.g., a finger assembly in set 502 of finger assemblies) based on modified illumination slit uniformity calibration data. In some embodiments, determining the optimal position of the finger assembly can be achieved using appropriate mechanical or other methods and may include determining the optimal position of the finger assembly in any embodiment or any combination of the embodiments described above with reference to Figures 1 to 7 and below with reference to Figure 9.

[0110]

[0125] Optionally, in any operation 808, the method may include determining a change in the shape of the finger assembly by the controller.

[0111]

[0126] In some embodiments, determining a change in the shape of a finger assembly may include, by the controller, determining a change in the position of the optical edge of the fingertip based on the elongation of the fingertip in response to the fingertip of the finger assembly being exposed to DUV or EUV radiation, and by the controller determining a change in the shape of the finger assembly based on the determined change in the position of the optical edge of the fingertip of the finger assembly.

[0112]

[0127] In some embodiments, determining a change in the shape of a finger assembly may include, by a controller, measuring a change in the position of a reference mark placed on the finger assembly, and determining a change in the shape of the finger assembly based on the measured change in the position of the reference mark. In some embodiments, determining a change in the shape of a finger assembly can be achieved by appropriate mechanical or other methods, and may include determining a change in the shape of a finger assembly according to any embodiment or any combination of the embodiments described above with reference to Figures 1 to 7 and below with reference to Figure 9.

[0113]

[0128] Optionally, in any operation 810, the method may include the controller generating a control signal configured to instruct a motion control system coupled to the finger assembly to adjust the optimal position of the finger assembly based on modified illumination slit uniformity calibration data and a determined change in the shape of the finger assembly. In some embodiments, the generation of the control signal can be achieved by appropriate mechanical or other means and may include generating the control signal in any manner or any combination of any of the manners described above with reference to Figures 1 to 7 and below with reference to Figure 9.

[0114]

[0129] Optionally, in any operation 812, the method may include transmitting a control signal to the motion control system by the controller. In some embodiments, the transmission of the control signal can be achieved by appropriate mechanical or other means and may include transmitting the control signal in any manner or any combination of any of the manners described above with reference to Figures 1 to 7 and below with reference to Figure 9.

[0115]

[0130] Exemplary computing system

[0131] Aspects of this disclosure can be implemented in hardware, firmware, software, or any combination thereof. Aspects of this disclosure can also be implemented as instructions stored on a machine-readable medium that can be read and executed by one or more processors. Machine-readable instructions may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, machine-readable media may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, propagating signals of electrical, optical, acoustic or other forms (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Furthermore, firmware, software, routines, instructions, and combinations thereof may be described herein as performing specific actions. However, such descriptions are merely for convenience, and such actions actually originate from computing devices, processors, controllers, or other devices that execute firmware, software, routines, instructions, or combinations thereof, and it will be acknowledged that during execution, actuators or other devices (e.g., servo motors, robotic devices) may interact with the material world.

[0116]

[0132] Various embodiments can be implemented using one or more computing systems, such as the exemplary computing system 900 shown in Figure 9. The exemplary computing system 900 may be a dedicated computer capable of performing the functions described herein, such as the exemplary lighting uniformity correction system 500 shown in Figures 5A and 5B, any other suitable systems, subsystems, or components, or any combination thereof. The exemplary computing system 900 may include one or more processors (also called a central processing unit, i.e., a CPU), such as a processor 904. The processor 904 is connected to a communication infrastructure 906 (e.g., a bus). The exemplary computing system 900 may also include one or more user input / output devices 903, such as a monitor, keyboard, or pointing device, which communicate with the communication infrastructure 906 via one or more user input / output interfaces 902. The exemplary computing system 900 may also include main memory 908 (e.g., one or more primary storage devices), such as random access memory (RAM). The main memory 908 may include one or more levels of cache. Main memory 908 stores control logic (e.g., computer software) and / or data internally.

[0117]

[0133] The exemplary computing system 900 may also include secondary memory 910 (e.g., one or more secondary storage devices). The secondary memory 910 may include, for example, a hard disk drive 912 and / or a removable storage drive 914. The removable storage drive 914 may be a floppy disk drive, a magnetic tape drive, a compact disk drive, an optical storage device, a tape backup device, and / or any other storage device / drive.

[0118]

[0134] The removable storage drive 914 can interact with the removable storage unit 918. The removable storage unit 918 includes a computer-readable or computer-enabled storage device that internally stores computer software (control logic) and / or data. The removable storage unit 918 may be a floppy disk, magnetic tape, compact disk, DVD, optical storage disk, and / or any other computer data storage device. The removable storage drive 914 reads from and / or writes to the removable storage unit 918.

[0119]

[0135] In some embodiments, the secondary memory 910 may include other means, instruments, or other techniques for enabling the exemplary computing system 900 to access computer programs and / or other instructions and / or data. Such means, instruments, or other techniques may include, for example, a removable storage unit 922 and an interface 920. Examples of the removable storage unit 922 and interface 920 may include a program cartridge and cartridge interface (such as those found in video game devices), a removable memory chip (such as an EPROM or PROM) and associated socket, a memory stick and USB port, a memory card and associated memory card slot, and / or any other interface associated with a removable storage unit.

[0120]

[0136] The exemplary computing system 900 may further include a communication interface 924 (e.g., one or more network interfaces). The communication interface 924 allows the exemplary computing system 900 to communicate with and interact with any combination of remote devices, remote networks, remote entities, etc. (individually or collectively referred to as remote devices 928). For example, the communication interface 924 allows the exemplary computing system 900 to communicate with remote devices 928 via a communication path 926. The communication path 926 may be wired or wireless and may include any combination of LAN, WAN, Internet, etc. Control logic, data, or both may be transmitted to and from the exemplary computing system 900 via the communication path 926.

[0121]

[0137] The operations in the aforementioned embodiments of this disclosure can be implemented in a wide variety of configurations and architectures. Accordingly, some or all of the operations in the aforementioned embodiments can be performed in hardware, software, or both. In some embodiments, a tangible, non-temporary device or article of manufacture includes a tangible, non-temporary computer-usable or readable medium in which control logic (software) is stored, and is also referred to herein as a computer program product or program storage device. This includes, but is not limited to, an exemplary computing system 900, main memory 908, secondary memory 910, and removable storage units 918 and 922, as well as tangible articles embodying any combination thereof. Such control logic, when executed by one or more data processing devices (such as the exemplary computing system 900), causes such data processing devices to operate as described herein.

[0122]

[0138] Based on the teachings contained herein, it will be apparent to those skilled in the art how embodiments of this disclosure can be constructed and used with data processing devices, computer systems, and / or computer architectures other than those shown in Figure 9. In particular, embodiments of this disclosure can operate with software, hardware, and / or operating system embodiments other than those described herein.

[0123]

[0139] Embodiments may be further described using the following clauses. 1. A system, Uniformity correction system, Equipped with a controller, The uniformity correction system includes multiple finger assemblies. Multiple finger assemblies define the maximum exposure field of the uniformity correction system. A subset of multiple finger assemblies defines the exposure field for wafer exposure operations. The controller is Determine whether the exposure field is smaller than the maximum exposure field. In response to the determination that the exposure field is smaller than the maximum exposure field, the illumination slit uniformity calibration data associated with the maximum exposure field is modified to generate modified illumination slit uniformity calibration data associated with the exposure field. Based on modified illumination slit uniformity calibration data, the optimal position of a finger assembly within a subset of multiple finger assemblies is determined. A system that is configured in such a way. 2. The maximum exposure field corresponds to the maximum illumination slit width of the uniformity correction system. The exposure field corresponds to an illumination slit width smaller than the maximum illumination slit width, as described in Clause 1. 3. The maximum exposure field corresponds to the entire field of the uniformity correction system. The exposure field corresponds to a partial field of the uniformity correction system, as described in Clause 1. 4. The uniformity correction system further includes a motion control system, which is coupled to the finger assembly and configured to adjust the optimal position of the finger assembly. The controller further, Determine the first change in the shape of the finger assembly, Based on the modified illumination slit uniformity calibration data and the first determined change in the shape of the finger assembly, a control signal is generated which instructs the motion control system to adjust the optimal position of the finger assembly. The control signal is transmitted to the motion control system. The system described in Clause 1 is configured as follows. 5. The controller is further, Based on the elongation of the fingertips in response to exposure of the fingertips of the finger assembly to deep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiation, a second change in the position of the optical edge of the fingertips is determined. Based on a determined second change in the position of the optical edge of the fingertip of the finger assembly, a first change in the shape of the finger assembly is determined. The system described in Clause 4 is configured as follows. 6. The controller further, Measure the second change in the position of the reference mark placed on the finger assembly. Based on the measured second change in the position of the reference mark, the first change in the shape of the finger assembly is determined. The system described in Clause 4 is configured as follows. 7. It is a controller, Determine whether the exposure field for wafer exposure operation is smaller than the maximum exposure field of the uniformity correction system. In response to the determination that the exposure field is smaller than the maximum exposure field, the illumination slit uniformity calibration data associated with the maximum exposure field is modified to generate modified illumination slit uniformity calibration data associated with the exposure field. Based on the modified illumination slit uniformity calibration data, the optimal position of the finger assembly in the uniformity correction system is determined. A device equipped with a controller configured in such a way. 8. The uniformity correction system includes multiple finger assemblies, The maximum exposure field is defined by multiple finger assemblies. The exposure field is defined by a subset of multiple finger assemblies. A subset of multiple finger assemblies includes a finger assembly. The apparatus described in Article 7. 9. The maximum exposure field corresponds to the maximum illumination slit width of the uniformity correction system. The exposure field corresponds to an illumination slit width smaller than the maximum illumination slit width. The apparatus described in Article 7. 10. The maximum exposure field corresponds to the entire field of the uniformity correction system. The exposure field corresponds to a partial field of the uniformity correction system. The apparatus described in Article 7. 11. The controller further, Determine the first change in the shape of the finger assembly, Based on the modified illumination slit uniformity calibration data and the first determined change in the shape of the finger assembly, a control signal is generated which is configured to instruct the motion control system coupled to the finger assembly to adjust the optimal position of the finger assembly. The control signal is transmitted to the motion control system. The apparatus described in Clause 7, configured as such. 12. The controller further, Based on the elongation of the fingertips in response to exposure of the fingertips of the finger assembly to deep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiation, a second change in the position of the optical edge of the fingertips is determined. Based on a determined second change in the position of the optical edge of the fingertip of the finger assembly, a first change in the shape of the finger assembly is determined. The apparatus described in Clause 11, configured as such. 13. The controller further, Measure the second change in the position of the reference mark placed on the finger assembly. Based on the measured second change in the position of the reference mark, the first change in the shape of the finger assembly is determined. The apparatus described in Clause 11, configured as such. 14. A method for adjusting the uniformity of the illumination slit in a lithography apparatus, The controller determines whether the exposure field for the wafer exposure operation is smaller than the maximum exposure field of the uniformity correction system, In response to the determination that the exposure field is smaller than the maximum exposure field, the controller modifies the illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. The controller determines the optimal position of the finger assembly of the uniformity correction system based on the modified illumination slit uniformity calibration data, A method that includes this. 15. The uniformity correction system includes multiple finger assemblies, The maximum exposure field is defined by multiple finger assemblies. The exposure field is defined by a subset of multiple finger assemblies. A subset of multiple finger assemblies includes a finger assembly. The method described in Article 14. 16. The maximum exposure field corresponds to the maximum illumination slit width of the uniformity correction system. The exposure field corresponds to an illumination slit width smaller than the maximum illumination slit width. The method described in Article 14. 17. The maximum exposure field corresponds to the entire field of the uniformity correction system. The exposure field corresponds to a partial field of the uniformity correction system, as described in Clause 14. 18. The controller determines the first change in the shape of the finger assembly, The controller generates a control signal configured to instruct the motion control system coupled to the finger assembly to adjust the optimal position of the finger assembly based on modified illumination slit uniformity calibration data and a determined first change in the shape of the finger assembly. The controller transmits control signals to the motion control system, The method described in Clause 14, further including the method described in Clause 14. 19. Determining the first change in the shape of the finger assembly is The controller determines a second change in the position of the optical edge of the fingertip based on the elongation of the fingertip in response to exposure of the fingertip of the finger assembly to deep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiation, The controller determines a first change in the shape of the finger assembly based on a determined second change in the position of the optical edge of the fingertip of the finger assembly, The method described in Article 18, including the method described in Article 18. 20. Determining the first change in the shape of the finger assembly is The controller measures a second change in the position of a reference mark placed on the finger assembly, The controller determines a first change in the shape of the finger assembly based on a measured second change in the position of the reference mark, The method described in Article 18, including the method described in Article 18.

[0124]

[0140] While this text specifically refers to the use of lithography equipment in the manufacture of ICs, it should be understood that the lithography equipment described herein has other applications. For example, these include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memory, flat panel displays, LCDs, and thin-film magnetic heads. In light of these alternative applications, it will be recognized by those skilled in the art that where the terms “wafer” or “die” are used herein, they may be considered synonymous with the more general terms “substrate” or “target portion,” respectively. The substrates described herein may be processed before or after exposure using, for example, a track unit (usually a tool that coats a layer of resist onto the substrate and develops the exposed resist), a metronome unit, and / or an inspection unit. Where appropriate, the disclosure herein may be applied to the above and other substrate processing tools. Furthermore, the substrate may be processed multiple times, for example, to produce a multilayer IC, and therefore the term substrate as used herein may also refer to a substrate that already contains multiple processed layers.

[0125]

[0141] It should be understood that the terms and technical descriptions contained herein are for illustrative purposes only and not for limitation, and therefore, the terms and technical descriptions contained herein should be interpreted by those skilled in the art in light of the teachings contained herein.

[0126]

[0142] As used herein, the term “substrate” refers to a material on which a layer of material is added. In some embodiments, the substrate itself may be patterned, as may the added material on it, or it may remain patternless.

[0127]

[0143] The examples disclosed herein illustrate, but are not limiting, embodiments of the disclosure. Other appropriate modifications and adaptations of various conditions and parameters commonly found in the art and obvious to those skilled in the art are also within the spirit and scope of the disclosure.

[0128]

[0144] While specific embodiments of this disclosure have been described above, it is likely that other embodiments may also be implemented. This statement is not intended to limit the embodiments of this disclosure.

[0129]

[0145] It will be acknowledged that the section used to interpret the claims is the "Modes for Carrying Out the Invention," not the "Background Art," "Summary," and "Abstract" sections. The "Summary" and "Abstract" sections may describe one or more exemplary embodiments, though not all, that the inventors envision, and are not intended to limit in any way the embodiments of the present invention and the appended claims.

[0130]

[0146] Some aspects of this disclosure have been described above using function-building blocks that demonstrate the implementation of specified functions and their relationships. For convenience of description, the boundaries of these function-building blocks are arbitrarily defined herein. Alternative boundaries may be defined, provided that the specified functions and their relationships are adequately implemented.

[0131]

[0147] The foregoing descriptions of specific aspects of this disclosure are sufficient to illustrate the general nature of those aspects, and by applying knowledge of the art, such specific aspects can be readily modified and / or adapted for various applications without unnecessary experimentation and without departing from the general concepts of this disclosure. Accordingly, such adaptations and modifications are intended to be within the meaning and scope of equivalents of the disclosed aspects, based on the teachings and guidance presented herein.

[0132]

[0148] The breadth and scope of this disclosure should not be limited by any of the exemplary embodiments or designs described above, but should be defined solely by the following claims and their equivalents.

Claims

1. It is a system, Uniformity correction system, Equipped with a controller, The uniformity correction system includes a plurality of finger assemblies, The plurality of finger assemblies define the maximum exposure field of the uniformity correction system, The subset of the aforementioned finger assemblies defines the exposure field for wafer exposure operation, The aforementioned controller, Determine whether the exposure field is smaller than the maximum exposure field. In response to the determination that the exposure field is smaller than the maximum exposure field, the illumination slit uniformity calibration data associated with the maximum exposure field is modified to generate modified illumination slit uniformity calibration data associated with the exposure field. Based on the modified illumination slit uniformity calibration data, the optimal position of the finger assembly within the subset of the plurality of finger assemblies is determined. A system that is configured in such a way.

2. The maximum exposure field corresponds to the maximum illumination slit width of the uniformity correction system. The system according to claim 1, wherein the exposure field corresponds to an illumination slit width smaller than the maximum illumination slit width.

3. The maximum exposure field corresponds to all fields of the uniformity correction system, The system according to claim 1, wherein the exposure field corresponds to a partial field of the uniformity correction system.

4. The uniformity correction system further includes a motion control system, which is coupled to the finger assembly and configured to adjust the optimal position of the finger assembly. The aforementioned controller further, Determine the first change in the shape of the finger assembly, Based on the modified illumination slit uniformity calibration data and the determined first change in the shape of the finger assembly, a control signal is generated which instructs the motion control system to adjust the optimal position of the finger assembly. The control signal is transmitted to the motion control system. The system according to claim 1, configured as described above.

5. The aforementioned controller further, Based on the elongation of the fingertip in response to exposure of the fingertip of the finger assembly to deep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiation, a second change in the position of the optical edge of the fingertip is determined. Based on the determined second change in the position of the optical edge of the fingertip of the finger assembly, the first change in the shape of the finger assembly is determined. The system according to claim 4, configured as described above.

6. The aforementioned controller further, The second change in the position of the reference mark placed on the finger assembly is measured. Based on the measured second change in the position of the reference mark, the first change in the shape of the finger assembly is determined. The system according to claim 4, configured as described above.

7. It is a controller, Determine whether the exposure field for wafer exposure operation is smaller than the maximum exposure field of the uniformity correction system. In response to the determination that the exposure field is smaller than the maximum exposure field, the illumination slit uniformity calibration data associated with the maximum exposure field is modified to generate modified illumination slit uniformity calibration data associated with the exposure field. Based on the modified illumination slit uniformity calibration data, the optimal position of the finger assembly of the uniformity correction system is determined. A device equipped with a controller configured in such a way.

8. The uniformity correction system includes a plurality of finger assemblies, The maximum exposure field is defined by the plurality of finger assemblies, The exposure field is defined by a subset of the plurality of finger assemblies, The subset of the plurality of finger assemblies includes the finger assembly, The maximum exposure field corresponds to the maximum illumination slit width of the uniformity correction system. The exposure field corresponds to an illumination slit width smaller than the maximum illumination slit width. The apparatus according to claim 7.

9. The maximum exposure field corresponds to all fields of the uniformity correction system, The exposure field corresponds to a partial field of the uniformity correction system, The aforementioned controller further, Determine the first change in the shape of the finger assembly, Based on the modified illumination slit uniformity calibration data and the determined first change in the shape of the finger assembly, a control signal is generated which instructs the motion control system coupled to the finger assembly to adjust the optimal position of the finger assembly. The control signal is transmitted to the motion control system. The apparatus according to claim 7, configured as described above.

10. The aforementioned controller further, Based on the elongation of the fingertip in response to exposure of the fingertip of the finger assembly to deep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiation, a second change in the position of the optical edge of the fingertip is determined. Based on the determined second change in the position of the optical edge of the fingertip of the finger assembly, the first change in the shape of the finger assembly is determined. The apparatus according to claim 9, configured as described above.

11. The aforementioned controller further, The second change in the position of the reference mark placed on the finger assembly is measured. Based on the measured second change in the position of the reference mark, the first change in the shape of the finger assembly is determined. The apparatus according to claim 9, configured as described above.

12. A method for adjusting the uniformity of the illumination slit in a lithography apparatus, The controller determines whether the exposure field for the wafer exposure operation is smaller than the maximum exposure field of the uniformity correction system, In response to the determination that the exposure field is smaller than the maximum exposure field, the controller modifies the illumination slit uniformity calibration data associated with the maximum exposure field to generate modified illumination slit uniformity calibration data associated with the exposure field. The controller determines the optimal position of the finger assembly of the uniformity correction system based on the modified illumination slit uniformity calibration data, A method that includes this.

13. The uniformity correction system includes a plurality of finger assemblies, The maximum exposure field is defined by the plurality of finger assemblies, The exposure field is defined by a subset of the plurality of finger assemblies, The subset of the plurality of finger assemblies includes the finger assembly, The maximum exposure field corresponds to the maximum illumination slit width of the uniformity correction system. The exposure field corresponds to an illumination slit width smaller than the maximum illumination slit width. The method according to claim 12.

14. The controller determines a first change in the shape of the finger assembly, The controller generates a control signal configured to instruct a motion control system coupled to the finger assembly to adjust the optimal position of the finger assembly based on the modified illumination slit uniformity calibration data and the determined first change in the shape of the finger assembly. The controller transmits the control signal to the motion control system, It further includes, The maximum exposure field corresponds to all fields of the uniformity correction system, The method according to claim 12, wherein the exposure field corresponds to a partial field of the uniformity correction system.

15. Determining the first change in the shape of the finger assembly is: The controller determines a second change in the position of the optical edge of the fingertip based on the elongation of the fingertip in response to exposure of the fingertip of the finger assembly to deep ultraviolet (DUV) radiation or extreme ultraviolet (EUV) radiation, The controller determines the first change in the shape of the finger assembly based on the determined second change in the position of the optical edge of the fingertip of the finger assembly, The method according to claim 14, including the method described in claim 14.

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