Method and system for determining reticle deformation

Abstract

A computer system is disclosed. The computer system is configured to: model a shape and / or deformation of a reticle; and controlling the operation of a lithographic process using the reticle in dependence on the modeled shape and / or deformation; wherein in order to model the shape and / or deformation of the reticle, the computer system is configured to: obtain initial reference shape data representative of the shape of the reticle; obtaining mask heating calibration (RHC) data including mask shape data and corresponding mask alignment (RA) measurement data at different mask temperatures; generating calibrated reference shape data in dependence on the initial reference shape data, the RHC data, and the RA measurements; and modeling the shape and / or deformation of the reticle in dependence on the calibrated reference shape data.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to European Application EP22216576.3 filed on December 23, 2022, and the entire content of this European application is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to techniques for improving the determination accuracy of mask deformation. The determined deformation can be relied upon to determine and apply process corrections to reduce mask - induced errors in the lithography process. Background Art

[0004] A lithographic apparatus is a machine configured to apply a desired pattern onto a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus can, for example, project a pattern of a patterning device (e.g., a mask, a reticle) onto a layer of radiation - sensitive material (resist) provided on a substrate.

[0005] To project a pattern onto a substrate, a lithographic apparatus can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features that can be formed on the substrate. Compared to lithographic apparatuses using deep - ultraviolet (DUV) radiation having a wavelength of, for example, 157 nm or 193 nm or 248 nm, a lithographic apparatus using extreme - ultraviolet (EUV) radiation having a wavelength in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on a substrate.

[0006] A lithographic apparatus can include a reticle stage for holding a patterning device (e.g., a reticle) to transfer a pattern to a substrate. Reticle heating and / or cooling may cause changes in reticle properties, which may affect the radiation beam path (e.g., focusing) and cause deformation of the patterned substrate (e.g., overlay error). A reticle heating model can be used to model and correct changes in reticle properties. Known reticle heating models rely on sensor - based methods to calibrate the reticle heating model using a reticle temperature sensor (RTS) and require a batch of production wafers for calibration. In some examples, this method can be inaccurate and inefficient because the RTS may exhibit errors, introduce unnecessary delays, and require rework of production wafers.

[0007] The shape of the reticle can also be deformed by other influences such as the clamping force applied to the reticle. If not compensated, all reticle shape deformations may increase the deformation in the patterned substrate (e.g., overlay error). Summary of the Invention

[0008] There is generally a need to improve known techniques for determining distortions in the shape of a reticle. The determined distortions can be relied upon to determine and process correct to reduce reticle-induced errors in a lithography process. This can avoid rework of the produced substrate and / or increase the manufacturing throughput and yield of the lithography process.

[0009] According to a first aspect of the present invention, there is provided a computer system configured to: model the shape and / or distortion of a reticle; and control the operation of a lithography process using the reticle depending on the modeled shape and / or distortion; wherein, in order to model the shape and / or distortion of the reticle, the computer system is configured to: obtain initial reference shape data representing the shape of the reticle; obtain reticle heating calibration (RHC) data including reticle shape data and corresponding reticle alignment (RA) measurement data at different reticle temperatures; generate calibrated reference shape data depending on the initial reference shape data, the RHC data, and the RA measurements; and model the shape and / or distortion of the reticle depending on the calibrated reference shape data.

[0010] According to a second aspect of the present invention, there is provided a method comprising: modeling the shape and / or distortion of a reticle; and controlling the operation of a lithography process using the reticle depending on the modeled shape and / or distortion; wherein modeling the shape and / or distortion of the reticle comprises: obtaining initial reference shape data representing the shape of the reticle; obtaining reticle heating calibration (RHC) data including reticle shape data and corresponding reticle alignment (RA) measurement data at different reticle temperatures; generating calibrated reference shape data depending on the initial reference shape data, the RHC data, and the RA measurements; and modeling the shape and / or distortion of the reticle depending on the calibrated reference shape data.

[0011] According to a third aspect of the present invention, there is provided a system comprising: the computer system according to the first aspect; and a lithography apparatus; wherein the computer system is configured to control the operation of the lithography apparatus.

[0012] According to a fourth aspect of the present invention, there is provided a device manufacturing method using a lithography process, the device manufacturing method comprising the method according to the second aspect.

[0013] According to a fifth aspect of the present invention, there is provided a non-transitory computer-readable medium program comprising computer-readable instructions configured to cause a processor to control a lithography apparatus according to the method of the second aspect.

[0014] The implementation of any of the techniques described above may include an EUV light source, a DUV light source, a system, a method, a process, a device, and / or an apparatus. Details of one or more implementations are set forth in the accompanying drawings and the following description. Other features will be apparent from the specification, the drawings, and the claims.

[0015] Other features and exemplary aspects of the aspects, as well as the structures and operations of the various aspects, are described in detail below with reference to the accompanying drawings. It should be noted that the aspects are not limited to the specific aspects described herein. These aspects are presented herein for illustrative purposes only. Based on the teachings included herein, additional aspects will be apparent to those skilled in the relevant art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate the aspects and, together with the description, further serve to explain the principles of the aspects and enable those skilled in the relevant art to make and use the aspects.

[0017] Figure 1 is a schematic diagram of a lithography apparatus according to an exemplary aspect.

[0018] Figure 2A is a schematic diagram of a lithography cell according to an exemplary aspect.

[0019] Figure 2B is a schematic diagram of an overall lithography including a computer system for optimizing a lithography process according to an exemplary aspect.

[0020] Figure 3A is a schematic bottom perspective view of a reticle stage and a reticle according to an exemplary aspect.

[0021] Figure 3B Figure 3A A schematic bottom plan view of the reticle stage shown in.

[0022] Figure 4A is a schematic top perspective view of a reticle exchange device according to an exemplary aspect.

[0023] Figure 4B is Figure 4A A schematic partial cross-sectional view of the reticle exchange device shown in.

[0024] Figure 5 and Figure 6 are schematic diagrams of a reticle calibration method according to an exemplary aspect.

[0025] Figure 7 and Figure 8 are for according to an exemplary aspect Figure 5 and Figure 6Schematic diagram of the k parameter of the mask calibration method shown in

[0026] Figure 9 and Figure 10 Illustrates a mask calibration diagram according to an exemplary aspect.

[0027] Figure 11 Shows a deterministic mask heating model.

[0028] Figure 12 Shows a deterministic mask heating model according to the first embodiment.

[0029] Figure 13 Shows the difference in the modeled ratio of overlap to mask temperature when processing a batch of substrates for both a known model and the model according to the first embodiment.

[0030] Figure 14 Schematically shows the overlap error that may be caused by the temperature of the mask without performing a process that does not correct for this source of overlap error.

[0031] Figure 15 Shows how to obtain an RA measurement for a process performed on the first of a batch of substrates according to known techniques.

[0032] Figure 16 Shows how to obtain an RA measurement for a process performed on a batch of substrates according to known techniques.

[0033] Figure 17 Technique for obtaining an RA measurement for a process performed on a batch of substrates according to the fourth embodiment.

[0034] Figure 18 Is a flowchart of the process according to the first embodiment.

[0035] Figure 19 Is a flowchart of the process according to the second embodiment.

[0036] Figure 20 Is a flowchart of the process according to the third embodiment.

[0037] Figure 21 Is a flowchart of the process according to the fourth embodiment.

[0038] Figure 22 Is a flowchart of the process according to the fifth embodiment.

[0039] Features of aspects and exemplary aspects will be apparent from the detailed description set forth below in conjunction with the accompanying drawings, in which like reference numerals throughout the drawings identify corresponding elements. In the drawings, like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. Additionally, generally, the leftmost digit of a reference numeral identifies the drawing in which the reference numeral first appears. The drawings provided throughout this disclosure are not to be construed as being drawn to scale unless otherwise indicated. Detailed Description

[0040] This specification incorporates by reference one or more aspects of the features of the present invention. The disclosed aspects are merely illustrative of the invention. The scope of the invention is not limited to the disclosed aspects. The invention is defined by the appended claims.

[0041] The aspects described and references in this specification to "one aspect", "aspect", "example aspect", "exemplary aspect", etc. indicate that the described aspects may include a particular feature, structure, or characteristic, but each aspect may not necessarily include the particular feature, structure, or characteristic. Moreover, these phrases need not refer to the same aspect. Further, when a particular feature, structure, or characteristic is described in connection with an aspect, it is understood that such feature, structure, or characteristic, whether or not explicitly described, is within the knowledge of those skilled in the art in connection with other aspects.

[0042] For ease of description, spatially relative terms, such as "under", "below", "lower", "above", "on", "upper", and like terms, may be used herein to describe the relationship of one element or feature shown in the drawings to another element or feature. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may be interpreted accordingly.

[0043] As used herein, the term "about" or "substantially" or "approximately" indicates a given value that may vary based on a particular technology. Based on a particular technology, the term "about" or "substantially" or "approximately" may indicate a given value that varies within, for example, 1% to 15% of the value (e.g., ±1%, ±2%, ±5%, ±10%, or ±15% of the value).

[0044] As used herein, the term "parasitic thermal effect" refers to the initiation or internal stress and / or deformation of a reticle, such as mechanical stress and / or deformation resulting from heating and / or cooling the reticle (e.g., by resistive heating, gas flow cooling, exposing the reticle to a dose of radiation, etc.) or clamping and / or holding the reticle on a reticle stage.

[0045] As used herein, the term "non-production substrate" refers to a substrate (e.g., a wafer) that is not part of a production lot and is not fabricated into a device (e.g., an IC chip) by a lithography process. For example, a non-production substrate can be a chuck temperature control (CTC) wafer or a calibration wafer for a mask calibration method, e.g., to calibrate a mask heating model and to conform the mask by exposing the mask and the CTC wafer to a dose of radiation and measuring mask alignment and / or mask temperature.

[0046] As used herein, the term "production substrate" refers to a substrate (e.g., a wafer) that is part of a production lot and is fabricated into a device (e.g., an IC chip) by a lithography process. For example, a production substrate can be a wafer (e.g., silicon) that is used for the fabrication and on-line real-time calibration of a mask heating model, e.g., by exposing the mask and the wafer to a dose of radiation and measuring mask alignment and / or mask temperature.

[0047] As used herein, the term "mask heating model" refers to a modal deformation method (e.g., analysis of different mask mode shapes) to determine mask heating effects based on mask alignment and / or mask shape deformation and a finite element model (FEM) (e.g., COMSOL). For example, a mask heating model can be a deterministic (e.g., no random future states) or non-deterministic (e.g., including random future states) mask heating effect. In addition, a mask heating model can be regarded as a mask heating execution algorithm (RHEA) that uses on-line modal calibration to determine baseline mask heating kinetics. A mask heating model can be calibrated by exposing the mask and a non-production substrate to a dose of radiation for on-line real-time calibration of the mask heating model. In some aspects, e.g., a mask heating model can be calibrated by exposing the mask and a production substrate to a dose of radiation for on-line real-time calibration of the mask heating model. Other mask heating models utilize sensor-based methods (e.g., using RTS measurements) to calibrate the mask heating model. This is further described in detail in U.S. Patent No. 10,429,749, U.S. Patent No. 10,281,825, and U.S. Publication No. 2020 / 0166854, which are incorporated herein by reference in their entireties.

[0048] Reticle heating causes changes in reticle properties, and such changes may affect the radiation path and cause manufacturing errors (e.g., overlay). Reticle mechanical deformation (e.g., based on reticle temperature) can be calculated and decomposed into k parameters. Modal participation factor μ and time constant τ can be used to model each thermomechanical mode (e.g., eigenvector) in real time. The measured overlay and / or alignment can be used to model the associated k parameter drift, and the parameter drift can be used to calculate adjustments to the feedforward parameters μ and τ. The reticle heating model can also include adjusting the feedforward parameters μ and τ. This is further described in detail in U.S. Patent No. 10,429,749, U.S. Publication No. 2020 / 0166854, and WIPO Publication No. 2021 / 043519, which are incorporated herein by reference in their entireties.

[0049] As used herein, the term "finite element model" or "FEM" refers to a method for numerically solving differential equations (e.g., heat transfer equations, structural analysis equations, fluid flow equations, etc.) that arise in a reticle heating model. For example, baseline reticle heating kinetics can be analyzed via finite element analysis using FEM. This is further described in detail in U.S. Patent No. 10,429,749, U.S. Patent No. 10,281,825, and U.S. Publication No. 2020 / 0166854, which are incorporated herein by reference in their entireties.

[0050] As used herein, the term "key performance indicator" or "KPI" or "k parameter" refers to the coefficients of a polynomial that is fit to the deformation of reticle alignment marks and / or edge alignment marks. The k parameters parameterize the imaging deformation on each substrate field. For example, each k parameter can describe a certain image deformation component (e.g., scaling error, barrel distortion, pincushion distortion, etc.). For example, two important k parameters are k4, which represents the Y-axis magnification deformation (e.g., Figure 7 k4 / my as shown in Figure 8 ), and k18, which represents the Y-axis barrel distortion (e.g., k18 / cshpy as shown in ). The k parameters can be used as inputs to a lithography process (e.g., lithography apparatus LA, lithography cell LC, control system CL) to correct for deformation. This is further described in detail in U.S. Patent No. 10,429,749, U.S. Publication No. 2020 / 0166854, and WIPO Publication No. 2021 / 043519, which are incorporated herein by reference in their entireties.

[0051] As used herein, the term "online real-time calibration" refers to the calibration of a reticle heating model during the actual fabrication of a production substrate. For example, calibration of batch-produced substrates can be avoided, and rework of production substrates for calibration purposes can be reduced or avoided. Online calibration can be performed by exposing the reticle and the production substrate to a dose of radiation. Additionally, calibration can be performed in real time (e.g., at a real-time frame rate or a computational rate of 2.56 seconds or less).

[0052] Aspects of the present disclosure may be implemented in hardware, firmware, software, or any combination thereof. Aspects of the present disclosure may also be implemented as instructions stored on a machine-readable medium that can be read and executed by one or more processors. The machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, the machine-readable medium may include: read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). Additionally, firmware, software, routines, and / or instructions may be described herein as performing certain actions. However, it should be understood that these descriptions are for convenience only, and these actions are actually caused by a computing device, a processor, a controller, or other devices that execute the firmware, software, routines, instructions, etc.

[0053] However, before describing these aspects in more detail, it is instructive to present an example environment in which aspects of the present disclosure may be implemented.

[0054] Exemplary lithography system

[0055] Figure 1 A lithography system is shown that includes a radiation source SO and a lithography apparatus LA. The radiation source SO is configured to generate an EUV and / or DUV radiation beam B and supply the EUV and / or DUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA includes an illumination system IL, a support structure MT (e.g., a mask table, a reticle stage, a reticle platform) configured to support a patterning device MA (e.g., a mask, a reticle), a projection system PS, and a substrate table WT configured to support a substrate W.

[0056] The illumination system IL is configured to condition an EUV and / or DUV radiation beam B before the EUV and / or DUV radiation beam B is incident on the patterning device MA. Additionally, the illumination system IL may include a faceted field mirror device 10 and a faceted pupil mirror device 11. The faceted field mirror device 10 and the faceted pupil mirror device 11 together provide the EUV and / or DUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. As a supplement or alternative to the faceted field mirror device 10 and the faceted pupil mirror device 11, the illumination system IL may include other mirrors or devices.

[0057] After being conditioned thus, the EUV and / or DUV radiation beam B interacts with the patterning device MA. This interaction may be reflective (as shown), which may be preferred for EUV radiation. This interaction may be transmissive, which may be preferred for DUV radiation. Due to this interaction, a patterned EUV and / or DUV radiation beam B' is produced. The projection system PS is configured to project the patterned EUV and / or DUV radiation beam B' onto a substrate W. For this purpose, the projection system PS may include a plurality of mirrors 13, 14 configured to project the patterned EUV and / or DUV radiation beam B' onto a substrate W held by a substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV and / or DUV radiation beam B', thus forming an image of features smaller than the corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is Figure 1 illustrated as having only two mirrors 13, 14 in [ ], the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0058] The substrate W may include a previously formed pattern. In such a case, the lithographic apparatus LA aligns the image formed by the patterned EUV and / or DUV radiation beam B' with the previously formed pattern on the substrate W.

[0059] Exemplary lithography cell

[0060] Figure 2AShows a lithography cell LC, which is sometimes also referred to as a lithography cell or cluster. The lithography apparatus LA may form part of the lithography cell LC. The lithography cell LC may also include one or more devices for performing pre-exposure and post-exposure processes on a substrate. Conventionally, these devices include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, a chill plate CH, and a bake plate BK. A substrate transfer device or robot RO picks up substrates from the input / output ports I / O1, I / O2, moves the substrates between different process devices, and transfers the substrates to the feed table LB of the lithography apparatus LA. These devices, often collectively referred to as a track or a coat and develop system, are under the control of a track or coat and develop system control unit TCU, which is itself controlled by a management control system SCS that also controls the lithography apparatus LA via a lithography control unit LACU. Thus, the different devices can be operated to maximize throughput and processing efficiency.

[0061] In order to correctly and consistently expose the substrate W exposed by the lithography apparatus LA, it is desirable to inspect the substrate to measure properties of the patterned substrate, such as overlay errors between subsequent layers, line thickness, critical dimension (CD), etc. For this purpose, an inspection tool (e.g., a metrology tool MT) may be included in the lithography cell LC and / or the lithography apparatus LA. If an error is detected, the exposure of subsequent substrates or other processing steps to be performed on the substrate W can be adjusted, especially if the inspection is performed before the other substrates W in the same lot or batch are still to be exposed or processed.

[0062] An inspection device, which may also be referred to as a metrology device or metrology tool MT, is for determining the properties of the substrate W and, in particular, how the properties of different substrates W vary or how the properties associated with different layers of the same substrate W vary between different layers. The inspection device is alternatively configured to identify defects on the substrate W and may, for example, be part of the lithography cell LC, integrated into the lithography apparatus LA, and / or be a separate device. The inspection device can measure properties on a latent image (e.g., an image in the resist layer after exposure), a semi-latent image (e.g., an image in the resist layer after a post-exposure bake step), a developed resist image (e.g., an image in which the exposed or unexposed portions of the resist have been removed), or an etched image (e.g., an image after a pattern transfer step such as etching).

[0063] Exemplary computer system

[0064] Figure 2BShows a computer system CL, also referred to as a controller or a processor. The computer system CL can be part of a lithography unit LC, integrated into a lithography apparatus LA, and / or be a separate device. The computer system CL is configured to optimize the lithography process, such as calibrating a mask heating model. Generally, the patterning process in a lithography apparatus LA is one of the most critical steps in a process, which requires high accuracy in the sizing and placement of structures on a substrate W. To ensure such high accuracy, three systems can be combined in a so-called "integrated" control environment schematically depicted in Figure 2B As shown in Figure 2B The "integrated" environment can include a lithography apparatus LA, a computer system CL, and a metrology tool MT. For example, the lithography apparatus LA (the first system) can be connected to the computer system CL (the second system) and the metrology tool MT (the third system).

[0065] The key to such integrated lithography is to optimize the collaboration between these three systems to optimize the lithography process, such as to enhance the overall process window and provide a tight control loop to ensure that the patterning performed by the lithography apparatus LA remains within the process window. The process window defines a range of process parameters (e.g., dose, focus, overlay, etc.) within which a particular manufacturing process produces a defined result, such as a functional semiconductor device, and generally within which process parameter variations in the lithography process or patterning process are allowed.

[0066] The computer system CL can, for example, use a design layout to be patterned (e.g., a part of the design layout) to predict which resolution enhancement techniques to use and perform computational lithography simulations and calculations, such as to determine which mask layouts and lithography apparatus settings achieve the maximum overall process window for the patterning process (shown by the double arrow in the first scale SC1 in Figure 2B ). Generally, the resolution enhancement techniques are arranged to match the patterning capabilities of the lithography apparatus LA. The computer system CL can also be used to detect where the lithography apparatus LA is currently operating within the process window (e.g., using an input from the metrology tool MT) to predict, for example, whether defects are likely to occur due to sub-optimal processing (shown by the arrow pointing to "0" in the second scale SC2 in Figure 2B ).

[0067] The metrology tool MT can provide an input to the computer system CL, for example, to enable accurate simulations and predictions. For example, the metrology tool MT can provide alignment information. The metrology tool MT can provide feedback (e.g., via the computer system CL) to the lithography apparatus LA to identify, for example, possible drifts in the calibration state of the lithography apparatus LA (in Figure 2Bas shown by the plurality of arrows in the third scale SC3). During the lithography process, it is desirable to frequently measure the resulting structures, for example, for process control and verification. For example, different types of metrology tools MT can be used to measure one or more properties regarding the lithography apparatus LA, the substrate W to be patterned, and / or the mask alignment. This is described in further detail in U.S. Patent No. 11,099,319 and WIPO Publication No. 2021 / 043519, which are incorporated herein by reference in their entireties.

[0068] Exemplary mask platform and mask

[0069] Figure 3A and Figure 3B FIG. shows a schematic diagram of a mask platform 200 according to an exemplary aspect. Figure 3A is a schematic bottom perspective view of a mask platform 200 and a mask 300 according to an example aspect. Figure 3B is Figure 3A a schematic bottom plan view of the mask platform 200 and the mask 300 shown in

[0070] The mask platform 200 (e.g., the support structure MT) can be used in a lithography apparatus (e.g., the lithography apparatus LA) to hold a patterning device (e.g., the patterning device MA). The mask platform 200 can include a bottom platform surface 202, a top platform surface 204, side platform surfaces 206, a clamp 250, a mask holder 224, and / or a mask 300. In some aspects, the mask platform 200 with the mask 300 can be implemented in the lithography apparatus LA. For example, the mask platform 200 can be the support structure MT in the lithography apparatus LA. In some aspects, the mask 300 can be disposed on the bottom platform surface 202 and held by the clamp 250. For example, as Figure 3A and Figure 3B shown in, the mask 300 can be disposed on a clamp 250 (e.g., an electrostatic clamp) at the center of the bottom platform surface 202, where the front side 302 of the mask faces vertically away from the bottom platform surface 202. In some aspects, the mask holder 224 can be disposed on the bottom platform surface 202. For example, as Figure 3A and Figure 3B shown in, the mask 300 can be disposed at the center of the bottom platform surface 202 and fastened by the mask holders 224 adjacent to each corner of the mask 300.

[0071] In some lithography apparatuses, such as the lithography apparatus LA, the mask platform 200 with the clamp 250 can be used to hold and position the mask 300 for scanning or patterning operations. In some aspects, as Figure 3A and Figure 3BAs shown in, the reticle stage 200 may include a first encoder 212 and a second encoder 214 for positioning operations. For example, the first encoder 212 and the second encoder 214 may be interferometers. The first encoder 212 may be attached along a first direction of the reticle stage 200, such as the lateral direction (i.e., the X direction). And, the second encoder 214 may be attached along a second direction of the reticle stage 200, such as the longitudinal direction (i.e., the Y direction).

[0072] As Figure 3A and Figure 3B shown in, the reticle 300 may include a reticle front side 302, alignment marks 310, and / or edge alignment marks 320. The alignment marks 310 are configured to measure the alignment of the reticle 300 with a substrate (e.g., substrate W, non-production substrate, production substrate). In some aspects, as Figure 3A and Figure 3B shown in, one or more alignment marks 310 may be provided at the corners and / or center of the reticle 300 for RA measurement. The edge alignment marks 320 are configured to measure the reticle shape deformation of the reticle 300 due to thermal expansion when the reticle 300 is not within a predetermined temperature (e.g., at 22°C ± 0.2°C). In some aspects, as Figure 3A and Figure 3B shown in, one or more edge alignment marks 320 may be provided along the peripheral edges (e.g., horizontal and vertical edges) of the reticle 300 for reticle shape deformation (RSD) measurement. In some aspects, the results of the RA measurement and / or RSD measurement may be converted, for example, by FEM into the reticle temperature, where the FEM solves for the temperature based on the reticle alignment and / or reticle deformation.

[0073] Exemplary reticle exchange device

[0074] Figure 4A and Figure 4B show schematic diagrams of a reticle exchange device 100 according to an exemplary aspect. Figure 4A is a schematic top perspective view of a reticle exchange device 100 according to an exemplary aspect. Figure 4B is Figure 4A a schematic partial cross-sectional view of the reticle exchange device 100 shown in.

[0075] A reticle exchange device 100 can be configured to reduce reticle exchange time and thermal stress in a reticle 300 to increase, for example, the overall throughput in a lithography apparatus LA. In some aspects, the reticle exchange device 100 can reduce stress in the reticle 300 by removing the reticle 300 from a reticle platform 200 to an in-vacuum robot (IVR) 400. For example, the reticle exchange device 100 can quickly release the reticle 300 from a reticle holder 224 and a clamp 250, and transfer the reticle 300 to the IVR 400 to relieve the thermal stress in the reticle 300. In some aspects, the reticle exchange device 100 can reduce stress in the reticle 300 and increase throughput by releasing the reticle 300, transferring the reticle from the reticle platform 200 to the IVR 400, quickly returning, and clamping the reticle 300 back to the reticle platform 200. As Figure 4A and Figure 4B shown, the reticle exchange device 100 can include a reticle platform 200, a clamp 250, and an IVR 400.

[0076] The IVR 400 can include a reticle transfer device 402 having one or more reticle transfer device arms 404. In some aspects, the reticle transfer device 402 can be a rapid exchange device (RED) configured to rotate efficiently and minimize reticle exchange time. The reticle transfer device arm 404 can include a reticle bottom plate 406 configured to hold an object (e.g., the reticle 300). In some aspects, the reticle bottom plate 406 can be an extreme ultraviolet inner pod (EIP) for the reticle 300. The reticle bottom plate 406 includes a reticle bottom plate front side 407, and the reticle 300 includes a reticle back side 304.

[0077] As Figure 4A and Figure 4B shown, the reticle bottom plate 406 can hold the reticle 300 such that the reticle bottom plate front side 407 and the reticle back side 304 each face a bottom platform surface 202 and a clamp front side 252. For example, the reticle bottom plate front side 407 and the reticle back side 304 can face vertically away from the bottom platform surface 202 and the clamp front side 252. As Figure 4B shown, the reticle exchange device 100 can include a reticle exchange area 410, which is a cross-sectional area of the clamp 250, the reticle 300, the reticle bottom plate 406, and the reticle transfer device arm 404 during a reticle exchange process.

[0078] In one example, during a reticle exchange process, the reticle transfer device arm 404 of the reticle transfer device 402 positions the reticle 300 on the reticle bottom plate 406 towards the chuck 250 in the reticle exchange area 410. As described above, transferring the reticle from the reticle transfer device 402 to the chuck 250 and from the chuck to the reticle transfer device can relieve the thermal stress in the reticle 300 and reduce the parasitic thermal effects in the reticle 300.

[0079] Exemplary reticle calibration method

[0080] As discussed above, a lithographic apparatus (e.g., lithographic apparatus LA) can include a reticle stage (e.g., support structure MT, reticle stage 200) to hold a patterning device (e.g., patterning device MA, reticle 300) to transfer a pattern onto a substrate (e.g., substrate W). Heating and / or cooling of the reticle can cause changes in the reticle properties, which can affect the radiation beam path (e.g., focus) and cause deformation (e.g., overlay error) of the patterned substrate. The changes in the reticle properties can be modeled and corrected by a reticle heating model. Current reticle heating models rely on sensor-based ad-hoc methods to calibrate the reticle heating model using RTS and require calibration batches of production wafers.

[0081] In some examples, this method can be inaccurate and inefficient because RTS can exhibit errors, introduce unnecessary delays, and require rework of production wafers. In some aspects, RTS has a temperature gradient variation of about ±0.6 °C, which can cause an overlay mismatch of about 1 nm / °C. Additionally, in some aspects, each reticle temperature measurement by RTS takes about five seconds per wafer, which can introduce additional delays. Further, in some aspects, preconditioning of the reticle in the internal reticle library (IRL) can take additional time to condition (e.g., cool) the reticle to a desired temperature (e.g., 22 °C ± 0.2 °C), and some reticles can remain in the IRL longer than required. For example, due to preconditioning delays, delays of up to seven minutes can occur each time, which can translate to a production loss of up to thirty-five production wafers each time. Moreover, the changes in the thermo-mechanical properties of the reticle before calibration can be amplified and exacerbate the overlay mismatch (e.g., increasing from 1 nm / °C to more than 2.1 nm / °C). Additionally, production wafers used for calibration can be reworked over time, which can introduce additional delays and reduce the overall production volume.

[0082] Aspects of the reticle calibration apparatus, system, and method discussed below can increase the calibration accuracy and speed of the reticle heating model, reduce the adjustment time of the reticle, reduce the stress in the reticle, avoid rework of the production substrate, and / or increase the manufacturing throughput and yield of the lithography process.

[0083] Figures 5 to 8 FIGS. illustrate reticle calibration methods 500, 600 according to various exemplary aspects. Figure 5 is a schematic diagram of a reticle calibration method 500 according to an exemplary aspect. Figure 6 is a schematic diagram of a reticle calibration method 600 according to an exemplary aspect. Figure 7 is according to an exemplary aspect for Figure 6 a schematic diagram of the k4 parameter 700 of the reticle calibration method 600 shown in Figure 8 is according to an exemplary aspect for Figure 6 a schematic diagram of the k18 parameter 800 of the reticle calibration method 600 shown in

[0084] Figure 5 FIGS. illustrate a reticle calibration method 500 according to an exemplary aspect. The reticle calibration method 500 can be configured to reduce the effects of heating and / or cooling the reticle 300 during the lithography process. The reticle calibration method 500 can also be configured to increase the calibration accuracy and speed of the reticle heating model and increase the manufacturing throughput and yield of the lithography process. Although the reticle calibration method 500 is shown in Figure 5 as a stand-alone method and / or system, aspects of the present disclosure can be used in conjunction with other devices, systems, and / or methods such as, but not limited to, a lithography apparatus LA, a lithography cell LC, a computer system CL, a metrology tool MT, a support structure MT, a patterning device MA, a reticle exchange device 100, a reticle stage 200, a reticle 300, an IVR 400, and / or a reticle calibration method 600.

[0085] As Figure 5As shown in, the reticle calibration method 500 may include a reticle temperature 502, a process flow 504, an adjustment stage 510, a calibration stage 520, and / or a processing stage 530. The adjustment stage 510 may be configured to adjust an initial temperature of the reticle 300 to a predetermined temperature. In one aspect, the initial temperature of the reticle 300 may be in the range of about 20°C to about 24°C, depending on where the reticle 300 comes from in the lithography system (e.g., IRL, external metrology tool MT, reticle stage 200, integrated reticle inspection system (IRIS), etc.). For example, the reticle 300 may initially be in a "hot" state (e.g., a reticle temperature above 22°C ± 0.2°C), a "cold" state (e.g., a reticle temperature below 22°C ± 0.2°C), and a "perfect adjustment" state (e.g., a reticle temperature of 22°C ± 0.2°C). In one aspect, the adjustment stage 510 cools and / or heats the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C), as shown by adjusting the reticle temperature 512.

[0086] In some aspects, the reticle 300 may be adjusted (e.g., heated and / or cooled) by the IRL. For example, the reticle 300 may be placed in the IRL for about forty minutes to reach a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, the reticle 300 may be adjusted (e.g., heated and / or cooled) by an adjustment chamber that rapidly heats and / or cools the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C). For example, the adjustment chamber may include a resistive heater and / or nozzles to flow a gas (e.g., air, nitrogen, argon, helium, etc.) over the reticle 300 to rapidly heat and / or cool the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C), for example, for an initial temperature of about 22°C ± 2°C for about five minutes.

[0087] In some aspects, the adjustment stage 510 may include RA measurement and / or RSD measurement to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, one or more alignment marks 310 and / or one or more edge alignment marks 320 on the reticle 300 may be measured to determine the adjustment of the reticle temperature 512. In some aspects, the RSD measurement may be converted by the FEM to adjust the reticle temperature 512. In some aspects, the adjustment stage 510 may include an RA measurement between the reticle 300 and a non-production substrate. For example, the non-production substrate may include one or more CTC wafers for alignment and / or reticle temperature calibration.

[0088] In some aspects, the conditioning phase 510 may include conditioning the reticle 300 in the reticle stage 200 by using a fixed number of production substrates to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, if the reticle 300 is in a "hot" state (e.g., a reticle temperature above 22°C ± 0.2°C), up to about forty or fewer production substrates (e.g., about twenty-two to about twenty-six wafers) may be required to condition the production lot. However, if the reticle 300 is close to a "perfectly conditioned" state (e.g., 22°C ± 0.2°C), at least about two or more production substrates (e.g., about two to about six wafers) may be required to condition the production lot.

[0089] In some aspects, the conditioning phase 510 may include conditioning the reticle 300 in the reticle stage 200 by using decision-based and / or machine learning to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, decision-based and / or machine learning may include using regression, local regression, nonparametric local regression, kernel regression, multivariate adaptive regression, regression trees, Gaussian process regression, support vector regression, splines, smoothing splines, nearest neighbors, neural networks, adaptive windows, Kalman filtering, linear quadratic estimation, or combinations thereof.

[0090] In some aspects, the conditioning phase 510 may include conditioning the reticle 300 in the reticle stage 200 by using KPIs based on RA and / or RSD measurements to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, as Figure 7 and Figure 8 shown, the k4 parameter 700 and / or the k18 parameter 800 may be measured, and convergence of the average k4 parameter 710 and / or the average k18 parameter 810 (e.g., convergence ≥ 90%) may be used to determine the temperature of the reticle 300 and / or calibration of the reticle heating model.

[0091] The calibration phase 520 can be configured to calibrate the reticle heating model by exposing the reticle 300 and a non-production substrate to a dose of radiation. In one aspect, the initial temperature of the reticle 300 at the start of the calibration phase 520 is a predetermined temperature in a "perfectly conditioned" state (e.g., 22°C ± 0.2°C). In one aspect, the calibration phase 520 further heats the reticle 300 to the dose production temperature in a "hot" state (e.g., above 22°C ± 0.2°C), as shown in the calibrated reticle temperature 522. In one aspect, during the calibration phase 520, a non-production substrate is exposed to a dose of radiation to allow for in-line calibration of the reticle heating model in the production environment itself. In one aspect, an initial estimate of the parameter (e.g., x) to be calibrated is made based on the reticle heating model (e.g., FEM) and the reticle temperature (e.g., calibrated reticle temperature 522).

[0092] In some aspects, the initial estimate of the parameters for the reticle heating model can be based on the calibration (e.g., RA measurement) of one or more non-production substrates (e.g., CTC wafers). For example, the reticle heating model can be evaluated for one or more non-production substrates, e.g., until convergence (e.g., convergence ≥ 90%) of the parameters in the reticle heating model is achieved. In some aspects, once the calibration of the reticle heating model is completed with one or more non-production substrates, the production substrates in the production batch are started, and calibration based on RA measurement continues throughout the processing phase 530.

[0093] In some aspects, the calibration phase 520 can include RA measurement and / or RSD measurement to determine the temperature of the reticle 300. In some aspects, the calibration phase 520 can include in-line real-time calibration of the reticle heating model based on one or more non-production substrates and / or one or more non-production batches. For example, the reticle temperature in a specific phase (e.g., conditioning phase 510) can be compared between two different non-production substrates and / or non-production batches, and the difference (e.g., differential reticle temperature ) or trend (e.g., = 0.5°C) can be adjusted in the reticle heating model.

[0094] In some aspects, the calibration phase 520 can include evaluating the reticle heating model for each RA measurement between the reticle and multiple non-production substrates in a non-production batch. For example, the evaluation can include updating the parameter x (e.g., radiation dose, focus, alignment, etc.) of the lithography process by:

[0095]

[0096] where γ is a gain value and is configured to filter out noise. For example, γ can be equal to any number within the interval [-1, 1] (e.g., -1, -0.5, -0.1, 0.1, 0.5, 1). For example, the evaluation can include RA measurements for each of a plurality of non-production substrates until convergence (e.g., ≥90%) is achieved.

[0097] In some aspects, the calibration stage 520 can also be configured to condition (e.g., heat to) the mask 300 to a dose temperature by exposing the mask 300 and a non-production substrate to a dose of radiation. In one aspect, the initial temperature of the mask 300 at the start of the calibration stage 520 is a predetermined temperature (e.g., 22°C ± 0.2°C) in a "perfectly conditioned" state. In one aspect, the calibration stage 520 heats the mask 300 to the dose temperature (e.g., about 24°C), as shown in the calibrated mask temperature 522. In some aspects, the calibration stage 520 can include RA measurements and / or RSD measurements to determine the temperature of the mask 300. In some aspects, the non-production substrate can include one or more CTC wafers for dose calibration.

[0098] The processing stage 530 can be configured to process (e.g., fabricate) the production substrate by exposing the mask 300 and the production substrate to a dose of radiation based on a mask heating model. In one aspect, the initial temperature of the mask 300 at the start of the processing stage 530 is the dose temperature (e.g., about 24°C). In one aspect, the processing stage 530 further heats the mask 300 to the dose production temperature in a "hot" state (e.g., ≥24°C), as shown in the processed mask temperature 532. In one aspect, during the processing stage 530, the production substrate is exposed to a dose of radiation to allow for on-line calibration of the mask heating model in the production environment itself. In one aspect, an initial estimate of a parameter (e.g., x) to be calibrated is made based on the mask heating model (e.g., FEM) and the mask temperature (e.g., the processed mask temperature 532).

[0099] In some aspects, the processing stage 530 can also be configured to calibrate the mask heating model by exposing the mask 300 and the production substrate to a dose of radiation. In some aspects, once the calibration of the mask heating model is completed (e.g., during the calibration stage 520) with one or more non-production substrates, the production substrates in the production batch are started and calibration based on RA measurements continues throughout the processing stage 530.

[0100] In some aspects, the processing stage 530 may include RA measurements and / or RSD measurements to determine the temperature of the reticle 300. In some aspects, the processing stage 530 may include on-line real-time calibration of the reticle heating model based on one or more production substrates and / or one or more production lots. For example, the reticle temperature in a particular stage (e.g., the conditioning stage 510) may be compared between two different production substrates and / or production lots, and the difference (e.g., differential reticle temperature ) or trend (e.g., = 0.5 °C) may be adjusted in the reticle heating model.

[0101] In some aspects, the processing stage 530 may include evaluating the reticle heating model for each RA measurement between the reticle and a plurality of production substrates in a production lot. For example, the evaluation may include updating the parameter x (e.g., radiation dose, focus, alignment, etc.) of the lithography process by:

[0102]

[0103] where γ is a gain value and is configured to filter noise. For example, γ may be equal to any number within the interval [-1, 1] (e.g., -1, -0.5, -0.1, 0.1, 0.5, 1). For example, the evaluation may include RA measurements for each of a plurality of production substrates until convergence (e.g., ≥ 90%) is achieved.

[0104] In some aspects, the reticle calibration method 500 may include performing separate RA and RSD measurements for each stage (e.g., in the conditioning stage 510, the calibration stage 520, and the processing stage 530). For example, the RA measurements may be performed in each stage, and the RSD measurements may be performed only once in each stage. In some aspects, the decision-based and / or machine learning used in the conditioning stage 510 to determine the temperature of the reticle 300 may also be used in the calibration stage 520 and / or the processing stage 530.

[0105] In some aspects, the reticle calibration method 500 may be implemented by a computer system CL, which may act as a controller and / or a processor to control the various stages and measurements of the reticle calibration method 500. In some aspects, the reticle calibration method 500 may be implemented by a lithography apparatus LA, which may include a controller and / or a processor to control the various stages and measurements of the reticle calibration method 500. In some aspects, the reticle calibration method 500 may be implemented by a non-transitory computer-readable medium program on, for example, the computer system CL, which may act as a controller and / or a processor to control the various stages and measurements of the reticle calibration method 500.

[0106] Figure 5 Aspects of the reticle calibration method 500 shown, for example, in Figure 6 Aspects of the reticle calibration method 600 shown in may be similar. Like reference numerals are used to indicate Figure 5 features of aspects of the reticle calibration method 500 shown in Figure 6 and similar features of aspects of the reticle calibration method 600 shown in.

[0107] Figure 6 FIG. illustrates a reticle calibration method 600 according to an exemplary aspect. The reticle calibration method 600 may be configured to reduce the effects of heating and / or cooling the reticle 300 during a lithography process. The reticle calibration method 600 may also be configured to increase the calibration accuracy and speed of a reticle heating model and increase the manufacturing throughput and yield of the lithography process. Although the reticle calibration method 600 is shown in Figure 6 as a stand-alone method and / or system, aspects of the present disclosure may be used with other devices, systems, and / or methods such as, but not limited to, a lithography apparatus LA, a lithography cell LC, a computer system CL, a metrology tool MT, a support structure MT, a patterning device MA, a reticle exchange device 100, a reticle stage 200, a reticle 300, an IVR 400, and / or a reticle calibration method 500.

[0108] As Figure 6 shown, the reticle calibration method 600 may include a reticle temperature 602, a process flow 604, an adjustment phase 610, a stress reduction phase 620, a calibration phase 630, and / or a processing phase 640. The adjustment phase 610 may be configured to adjust an initial temperature of the reticle 300 to a predetermined temperature. In one aspect, the initial temperature of the reticle 300 may be in the range of about 20°C to about 24°C, depending on where the reticle 300 comes from in the lithography system (e.g., IRL, external metrology tool MT, reticle stage 200, IRIS, etc.). For example, the reticle 300 may initially be in a "hot" state (e.g., a reticle temperature above 22°C ± 0.2°C), a "cold" state (e.g., a reticle temperature below 22°C ± 0.2°C), and a "perfectly adjusted" state (e.g., a reticle temperature of 22°C ± 0.2°C). In one aspect, the adjustment phase 610 may include adjusting RA and RSD measurements 611 to determine the initial temperature of the reticle 300. In one aspect, the adjustment phase 610 cools and / or heats the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C), as Figure 6 shown by adjusting the reticle temperature 612 in.

[0109] In some aspects, the reticle 300 can be conditioned by an IRL (e.g., heating and / or cooling). For example, the reticle 300 can be placed in the IRL for approximately forty minutes to reach a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, the reticle 300 can be conditioned (e.g., heated and / or cooled) by a conditioning chamber that rapidly heats and / or cools the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C). For example, the conditioning chamber can include a resistive heater and / or nozzles to flow a gas (e.g., air, nitrogen, argon, helium, etc.) over the reticle 300 to rapidly heat and / or cool the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C), e.g., for an initial temperature of approximately 22°C ± 2°C for approximately five minutes.

[0110] In some aspects, the conditioning phase 610 can include one or more RA measurements and RSD measurements to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, as Figure 6 shown, conditioning RA and RSD measurements 611 can be made to determine the initial temperature of the reticle 300 in the conditioning phase 610. For example, one or more alignment marks 310 (shown in Figure 3A and Figure 3B ), and one or more edge alignment marks 320 (shown in Figure 3A and Figure 3B ) on the reticle 300 can be measured to determine reticle temperature conditioning 612. In some aspects, the RSD measurements can be converted by a FEM to reticle temperature conditioning 612. In some aspects, the conditioning phase 610 can include one or more RA measurements between the reticle 300 and a non-production substrate. For example, as Figure 6 shown, the conditioning phase 610 can include conditioning RA and RSD measurements 611, a second conditioning RA measurement 614 (if needed), a third conditioning RA measurement 616 (if needed), and / or a fourth conditioning RA measurement 618 (if needed) to periodically measure the reticle temperature 602 during the process flow 604 and determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, the non-production substrate can include one or more CTC wafers for alignment and / or reticle temperature calibration.

[0111] In some aspects, the conditioning phase 610 may include conditioning the reticle 300 in the reticle stage 200 by using a fixed amount of production substrates to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, if the reticle 300 is in a "hot" state (e.g., a reticle temperature above 22°C ± 0.2°C), up to about forty or fewer production substrates (e.g., about twenty-two to about twenty-six wafers) are required to condition the production lot. However, if the reticle 300 is close to a "perfectly conditioned" state (e.g., 22°C ± 0.2°C), at least about two or more production substrates (e.g., about two to about six wafers) are required to condition the production lot.

[0112] In some aspects, the conditioning phase 610 may include conditioning the reticle 300 in the reticle stage 200 by using decision-based and / or machine learning to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, decision-based and / or machine learning may include using regression, local regression, nonparametric local regression, kernel regression, multivariate adaptive regression, regression trees, Gaussian process regression, support vector regression, splines, smoothing splines, nearest neighbors, neural networks, adaptive windows, Kalman filtering, linear quadratic estimation, or combinations thereof. In some aspects, the timing specifications (e.g., the applied Kalman filtering) are aligned with the timing specifications (e.g., the process window) of the lithography process with a similar high accuracy. In some aspects, an adaptive window may be used to determine if there is any decay and / or drift of the KPIs (e.g., k4 parameter, k18 parameter). For example, four RA measurements may be made (e.g., the past three measurements and the current measurement) and a check is performed to verify if any changes have occurred between the RA measurements. If a change is detected, the conditioning phase 610 continues, while if no change is detected, the conditioning phase 610 is completed (e.g., stopped). In some aspects, the minimum time of the conditioning phase 610 is about one minute, and the maximum time of the conditioning phase 610 is about five minutes.

[0113] In some aspects, the conditioning phase 610 may include conditioning the reticle 300 in the reticle stage 200 by using KPIs based on RA and / or RSD measurements to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). For example, as Figure 7 and Figure 8 shown, the k4 parameter 700 and / or the k18 parameter 800 may be measured, and the convergence of the average k4 parameter 710 and / or the average k18 parameter 810 (e.g., convergence ≥ 90%) may be used to determine the temperature of the reticle 300 and / or the calibration parameters of the reticle heating model. For example, as Figure 6As shown in, the conditioning phase 610 may include conditioning the RA and RSD measurements 611, the second conditioned RA measurement 614, the third conditioned RA measurement 616, and / or the fourth conditioned RA measurement 618 to measure KPIs (e.g., the k4 parameter 700, the k18 parameter 800) to determine when the reticle 300 has reached a predetermined temperature (e.g., 22 °C ± 0.2 °C).

[0114] The stress reduction phase 620 may be configured to reduce parasitic thermal effects in the reticle 300. In one aspect, as Figure 6 shown in, the stress reduction phase 620 may include a removal step 621 and a zero-dose step 622. The removal step 621 may be configured to release stress from the reticle 300 and thereby reduce parasitic thermal effects by removing the reticle 300 from the reticle stage 200 to the IVR 400. The zero-dose step 622 may be configured to release stress from the reticle 300 and thereby reduce parasitic thermal effects by exposing the reticle 300 and a non-production substrate to zero-dose radiation. In one aspect, the initial temperature of the reticle 300 at the start of the stress reduction phase 620 is the predetermined temperature (e.g., 22 °C ± 0.2 °C) in a "perfect conditioning" state. In one aspect, the stress reduction phase 620 reduces parasitic thermal effects in the reticle 300 by releasing stress in the reticle 300 in the removal step 621 and then exposing the reticle 300 in the zero-dose step 622 to further reduce parasitic thermal effects, as shown in the stress reduction reticle temperature 624. In one aspect, the stress reduction phase 620 maintains the reticle 300 at the predetermined temperature (e.g., 22 °C ± 0.2 °C) in a "perfect conditioning" state. In one aspect, the zero-dose step 622 may include zero-dose RA and RSD measurements 623 to verify the temperature of the reticle 300.

[0115] In some aspects, stress in the reticle 300 may be reduced by removing the reticle 300 from the reticle stage 200 and quickly returning the reticle 300 to the reticle stage 200. For example, as Figure 4A and Figure 4B shown in, the reticle 300 may be released from the reticle carrier 224 and the chuck 250 on the reticle stage 200 and transferred to the reticle bottom plate 406 of the IVR 400, and then immediately transferred back to the reticle stage 200 and clamped by the reticle carrier 224 and the chuck 250. In some aspects, stress in the reticle 300 may be reduced by exposing the reticle 300 and a non-production substrate (e.g., a CTC wafer) to zero-dose radiation. For example, as Figure 6As shown in, after the removal step 621, the zero-dose step 622 can be started, and the reticle temperature can be verified again (e.g., via RA and / or RSD measurements). In some aspects, the stress reduction phase 620 can include RA measurements and / or RSD measurements to determine the temperature of the reticle 300. For example, as Figure 6 shown in, zero-dose RA and RSD measurements 623 can be performed to verify the initial temperature of the reticle 300 in the zero-dose step 622. In some aspects, the non-production substrate can include one or more CTC wafers for zero-dose calibration.

[0116] The calibration phase 630 can be configured to calibrate the reticle heating model by exposing the reticle 300 and the non-production substrate to a dose of radiation. In one aspect, the initial temperature of the reticle 300 at the start of the calibration phase 630 is a predetermined temperature in the "perfectly adjusted" state (e.g., 22°C ± 0.2°C). In one aspect, the calibration phase 630 can include calibrating the RA and RSD measurements 631 to verify the temperature of the reticle 300. In one aspect, the calibration phase 630 heats the reticle 300 to the dose temperature (e.g., above 22°C ± 0.2°C), as shown in the calibrated reticle temperature 632. In one aspect, during the calibration phase 630, the non-production substrate is exposed to a dose of radiation to allow in-situ calibration of the reticle heating model in the production environment. In one aspect, an initial estimate of the parameter (e.g., x) to be calibrated is made based on the reticle heating model (e.g., FEM) and the reticle temperature (e.g., the calibrated reticle temperature 632).

[0117] In some aspects, the initial estimate of the parameters for the reticle heating model can be based on the calibration (e.g., RA measurements) of one or more non-production substrates (e.g., CTC wafers). For example, the reticle heating model can be evaluated for one or more non-production substrates, e.g., until convergence (e.g., convergence ≥ 90%) of the parameters in the reticle heating model is achieved. In some aspects, once the calibration of the reticle heating model is completed with one or more non-production substrates, the production substrates in the production batch are started, and calibration based on RA measurements continues throughout the processing phase 640.

[0118] In some aspects, the calibration phase 630 can include RA measurements and / or RSD measurements to determine the temperature of the reticle 300. For example, as Figure 6As shown in, calibration RA and RSD measurements 631 can be performed to verify the initial temperature of the reticle 300 at the start of the calibration phase 630. In some aspects, the calibration phase 630 can include online real-time calibration based on the reticle heating model of one or more non-production substrates and / or one or more non-production lots. For example, the reticle temperature in a specific phase (e.g., the conditioning phase 610) can be compared between two different non-production substrates and / or non-production lots, and the difference (e.g., differential reticle temperature ) or trend (e.g., = 0.5 °C) can be adjusted in the reticle heating model.

[0119] In some aspects, the calibration phase 630 can include evaluating the reticle heating model for each RA measurement between the reticle 300 and multiple non-production substrates in a non-production lot. For example, the evaluation can include updating the parameter x of the lithography process (e.g., radiation dose, focus, alignment, etc.) by:

[0120]

[0121] where γ is a gain value and is configured to filter out noise. For example, γ can be equal to any number within the interval [-1, 1] (e.g., -1, -0.5, -0.1, 0.1, 0.5, 1). For example, the evaluation can include RA measurements for each of the multiple non-production substrates until convergence (e.g., ≥ 90%) is achieved.

[0122] In some aspects, the calibration phase 630 can also be configured to condition (e.g., heat to) the reticle 300 to the dose temperature by exposing the reticle 300 and the non-production substrate to a dose of radiation. In one aspect, the initial temperature of the reticle 300 at the start of the calibration phase 630 is a predetermined temperature (e.g., 22 °C ± 0.2 °C) in a "perfect conditioning" state. In one aspect, the calibration phase 630 heats the reticle 300 to the dose temperature (e.g., approximately 24 °C), as shown in the calibrated reticle temperature 632. In some aspects, the calibration phase 630 can include RA measurements and / or RSD measurements to determine the temperature of the reticle 300. For example, as Figure 6 shown in, calibration RA and RSD measurements 631 can be performed to verify the initial temperature of the reticle 300 in the calibration phase 630. In some aspects, the non-production substrate can include one or more CTC wafers for dose calibration.

[0123] The processing stage 640 may be configured to process (e.g., fabricate) a production substrate by exposing the reticle 300 and the production substrate to a dose of radiation based on a reticle heating model. In one aspect, the initial temperature of the reticle 300 at the start of the processing stage 640 is the dose temperature (e.g., about 24°C). In one aspect, the processing stage 640 may include processing RA and RSD measurements 641 to verify the temperature of the reticle 300. In one aspect, the processing stage 640 further heats the reticle 300 to the dose production temperature in the "hot" state (e.g., ≥24°C), as shown in the processing reticle temperature 642. In one aspect, during the processing stage 640, the production substrate is exposed to a dose of radiation to allow for on-line calibration of the reticle heating model in the production environment itself. In one aspect, an initial estimate of the parameter (e.g., x) to be calibrated is made based on the reticle heating model (e.g., FEM) and the reticle temperature (e.g., processing reticle temperature 642).

[0124] In some aspects, the processing stage 640 may also be configured to calibrate the reticle heating model by exposing the reticle 300 and the production substrate to a dose of radiation. In some aspects, once the calibration of the reticle heating model is completed using one or more non-production substrates (e.g., during the calibration stage 630), the production substrates in the production batch are started, and calibration based on RA measurements continues throughout the processing stage 640.

[0125] In some aspects, the processing stage 640 may include RA measurements and / or RSD measurements to determine the temperature of the reticle 300. For example, as Figure 6 shown, processing RA and RSD measurements 641 may be made to verify the initial temperature of the reticle 300 at the start of the processing stage 640. In some aspects, the processing stage 640 may include on-line real-time calibration of the reticle heating model based on one or more production substrates and / or one or more production batches. For example, the reticle temperature in a particular stage (e.g., the conditioning stage 610) may be compared between two different production substrates and / or production batches, and the difference (e.g., differential reticle temperature ) or trend (e.g., = 0.5°C) may be adjusted in the reticle heating model.

[0126] In some aspects, the processing stage 640 may include evaluating the reticle heating model for each RA measurement between the reticle 300 and multiple production substrates in the production batch. For example, the evaluation may include updating the parameter x (e.g., radiation dose, focus, alignment, etc.) of the lithography process by:

[0127]

[0128] where γ is a gain value and is configured to filter out noise. For example, γ can be equal to any number within the interval [-1, 1] (e.g., -1, -0.5, -0.1, 0.1, 0.5, 1). For example, the evaluation can include RA measurements for each of a plurality of production substrates until convergence (e.g., ≥90%) is achieved.

[0129] In some aspects, the reticle calibration method 600 can include performing separate RA and RSD measurements for each stage (e.g., in the adjustment stage 610, the stress reduction stage 620, the calibration stage 630, and the processing stage 640). For example, the RA measurements can be performed in each stage, and the RSD measurements can be performed only once in each stage. In some aspects, the decision-based and / or machine learning used in the adjustment stage 610 to determine the temperature of the reticle 300 can also be used in the stress reduction stage 620, the calibration stage 630, and / or the processing stage 640.

[0130] In some aspects, the reticle calibration method 600 can utilize a comprehensive reticle heating model to cover all possible heating kinetics. For example, the reticle calibration method 600 can avoid the calibration stage 630 by using one or more predetermined FEMs of the reticle heating model. In some aspects, the reticle calibration method 600 can utilize a central data pool to calibrate the reticle heating model. For example, the central data pool can include baselines and / or statistical values (e.g., parameters of the reticle heating model) based on various internal (e.g., in the resist) data. In some aspects, the reticle calibration method 600 can include a sinusoidal sweep exposure for both reticle heating model calibration and lens calibration. For example, by using a sinusoidal sweep exposure (e.g., a fixed period), different time constants can be extracted for the reticle heating model parameters and lens parameters used for calibration (e.g., through RA and / or RSD measurements).

[0131] In some aspects, the reticle calibration method 600 can be implemented by a computer system CL, which can be used as a controller and / or a processor to control the various stages and measurements of the reticle calibration method 600. In some aspects, the reticle calibration method 600 can be implemented by a lithography apparatus LA, which can include a controller and / or a processor to control the various stages and measurements of the reticle calibration method 600. In some aspects, the reticle calibration method 600 can be implemented by a non-transitory computer-readable medium program on, for example, the computer system CL, which can be used as a controller and / or a processor to control the various stages and measurements of the reticle calibration method 600.

[0132] Figure 7Illustrated is the k4 parameter 700 according to an exemplary aspect. The k4 parameter 700 can be configured to increase the calibration accuracy and speed of the reticle heating model. The k4 parameter 700 can also be configured to determine the temperature of the reticle 300. The k4 parameter 700 represents the Y-axis magnification distortion. Although the k4 parameter 700 is shown as an independent method and / or system in Figure 7 it can be used in conjunction with other devices, systems, and / or methods such as, but not limited to, a lithography apparatus LA, a lithography cell LC, a computer system CL, a metrology tool MT, a reticle calibration method 500, and / or a reticle calibration method 600.

[0133] As Figure 7 shown, the k4 parameter 700 can include an intensity (in arbitrary units) 702, a wafer number 704, and an average k4 parameter 710. In some aspects, the k4 parameter 700 can be measured based on the distortion measured by RA and / or RSD to determine the temperature of the reticle 300. For example, as Figure 7 shown, the average k4 parameter 710 can be measured on a certain number of wafers, and the convergence of the average k4 parameter 710 (e.g., ≥ 90%) can be used to determine the temperature of the reticle 300 and / or the calibration parameters of the reticle heating model of the reticle calibration method 500 and / or the reticle calibration method 600. In some aspects, the k4 parameter 700 can be measured to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C).

[0134] Figure 8 Illustrated is the k18 parameter 800 according to an exemplary aspect. The k18 parameter 800 can be configured to increase the calibration accuracy and speed of the reticle heating model. The k18 parameter 800 represents the Y-axis barrel distortion. Although the k18 parameter 800 is shown as an independent method and / or system in Figure 8 it can be used in conjunction with other devices, systems, and / or methods such as, but not limited to, a lithography apparatus LA, a lithography cell LC, a computer system CL, a metrology tool MT, a reticle calibration method 500, and / or a reticle calibration method 600.

[0135] As Figure 8 shown, the k18 parameter 800 can include an intensity (in arbitrary units) 802, a wafer number 804, and an average k18 parameter 810. In some aspects, the k18 parameter 800 can be measured based on the distortion measured by RA and / or RSD to determine the temperature of the reticle 300. For example, as Figure 8As shown in , the average k18 parameter 810 can be measured on a number of wafers, and the convergence (e.g., ≥ 90%) of the average k18 parameter 810 can be used to determine the temperature of the reticle 300 and / or the calibration parameters of the reticle heating model of the reticle calibration method 500 and / or the reticle calibration method 600. In some aspects, the k18 parameter 800 can be measured to determine when the reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C).

[0136] Exemplary reticle calibration graph

[0137] Figure 9 and Figure 10 Illustrates reticle calibration graphs 900, 1000 for reducing the effects of heating and / or cooling the reticle 300 during a lithography process, according to an exemplary aspect. Figure 9 Illustrates the reticle calibration graph 900 according to an exemplary aspect. It should be understood that not all steps in Figure 9 are required to implement the disclosure provided herein. Additionally, some of the steps may be performed simultaneously, continuously, and / or in a different order than shown in Figure 9 . The reticle calibration graph 900 will be described with reference to Figure 3A , Figure 3B , Figure 4A , Figure 4B , Figure 5 and Figure 6 . However, the reticle calibration graph 900 is not limited to those exemplary aspects.

[0138] In step 902, as shown in the examples of Figure 3A , Figure 3B , Figure 5 and Figure 6 , the reticle 300 is adjusted (e.g., heated and / or cooled) to adjust the initial temperature of the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, the reticle 300 can be adjusted (e.g., heated and / or cooled) by a conditioning slot that rapidly heats and / or cools the reticle 300 to the predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, one or more RA measurements and RSD measurements can be made to determine when the reticle 300 has reached the predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, decision-making and / or machine learning can be used to determine when the reticle 300 has reached the predetermined temperature (e.g., 22°C ± 0.2°C).

[0139] In step 904, as shown in Figure 3A , Figure 3B , Figure 4A , Figure 4B and Figure 6As shown in the example of, stress (e.g., release) in the reticle 300 is reduced and parasitic thermal effects in the reticle 300 are reduced. In some aspects, stress in the reticle 300 can be released by removing the reticle 300 from the reticle platform 200 to the IVR 400 and thereby reducing parasitic thermal effects. In some aspects, stress in the reticle 300 can be released by exposing the reticle 300 and a non-production substrate to a zero dose of radiation and thereby reducing parasitic thermal effects.

[0140] In step 906, as Figure 3A , Figure 3B , Figure 5 and Figure 6 As shown in the example of, the reticle heating model is calibrated by exposing the reticle 300 and a non-production substrate to a dose of radiation. In some aspects, an initial estimate of the parameters for the reticle heating model can be based on the calibration (e.g., RA measurement) of one or more non-production substrates (e.g., CTC wafers). In some aspects, RA measurements and / or RSD measurements can be performed to determine the temperature of the reticle 300. In some aspects, online real-time calibration of the reticle heating model can be based on one or more non-production substrates and / or one or more non-production lots. In some aspects, the reticle heating model can be evaluated for each RA measurement between the reticle 300 and multiple non-production substrates in a non-production lot.

[0141] In some aspects, during step 906, the reticle 300 is conditioned (e.g., heated) by exposing the reticle 300 and a non-production substrate to a dose of radiation. In some aspects, RA measurements and / or RSD measurements can be performed to determine the temperature of the reticle 300. In some aspects, the non-production substrate can include one or more CTC wafers for dose calibration.

[0142] In step 908, as Figure 3A , Figure 3B , Figure 5 and Figure 6 As shown in the example of, the production substrate is processed (e.g., manufactured) by exposing the reticle 300 and the production substrate to a dose of radiation based on the reticle heating model. In some aspects, RA measurements and / or RSD measurements can be performed to determine the temperature of the reticle 300. In some aspects, online real-time calibration of the reticle heating model can be based on one or more production substrates and / or one or more production lots. In some aspects, the reticle heating model can be evaluated for each RA measurement between the reticle 300 and multiple production substrates in a production lot.

[0143] Figure 10FIG. 1000 is a mask calibration diagram according to an exemplary aspect. It should be understood that not all steps in Figure 10 are required to implement the disclosure provided herein. Additionally, some of the steps may be performed simultaneously, continuously, and / or in a different order than shown in Figure 10 . The mask calibration diagram 1000 will be described with reference to Figure 3A , Figure 3B , Figure 4A , Figure 4B , Figure 5 and Figure 6 . However, the mask calibration diagram 1000 is not limited to those exemplary aspects.

[0144] In step 1002, as shown in the examples of Figure 3A , Figure 3B , Figure 5 and Figure 6 , the mask 300 is heated and / or cooled to a temperature (e.g., 22°C ± 0.2°C) based on RSD measurements. In some aspects, the RSD measurements may be converted by FEM to the mask temperature. In some aspects, the mask 300 may be heated and / or cooled by rapidly heating and / or cooling the adjustment slots of the mask 300. In some aspects, one or more RA measurements and RSD measurements may be made to determine when the mask 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, decision-based and / or machine learning may be used to determine when the mask 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C).

[0145] In step 1004, as shown in the examples of Figure 3A , Figure 3B , Figure 4A , Figure 4B and Figure 6 , the mask 300 is removed from the mask platform 200 and then returned to the mask platform 200 to relieve thermal stress. In some aspects, the stress (e.g., induced stress, internal strain) in the mask 300 may be relieved by removing the mask 300 from the mask platform 200 to the IVR 400 and rapidly returning the mask 300 from the IVR 400 to the mask platform 200, thereby reducing parasitic thermal effects.

[0146] In step 1006, as shown in the examples of Figure 3A , Figure 3B and Figure 6As shown in the example of, the reticle 300 and the non-production substrate are exposed to radiation at zero dose to reduce parasitic thermal effects. In some aspects, the stress (e.g., residual stress) in the reticle 300 can be released and / or relaxed by exposing the reticle 300 and the non-production substrate (e.g., CTC wafer) to radiation at zero dose, thereby reducing parasitic thermal effects.

[0147] In step 1008, as Figure 3A , Figure 3B , Figure 5 and Figure 6 As shown in the example of, the temperature of the reticle 300 is measured based on RSD measurement. In some aspects, RA measurement and / or RSD measurement can be performed to determine the temperature of the reticle 300.

[0148] In step 1010, as Figure 3A , Figure 3B , Figure 5 and Figure 6 As shown in the example of, the reticle 300 and the non-production substrate are exposed to a dose of radiation. In some aspects, RA measurement and / or RSD measurement can be performed to determine the temperature of the reticle 300. In some aspects, the non-production substrate can include one or more CTC wafers for dose calibration.

[0149] In step 1012, as Figure 3A , Figure 3B , Figure 5 and Figure 6 As shown in the example of, the temperature of the reticle 300 is measured based on RSD measurement, and the reticle heating model is calibrated based on the measured temperature of the reticle 300. In some aspects, RA measurement and / or RSD measurement can be performed to determine the temperature of the reticle 300. In some aspects, the initial estimate of the parameters for the reticle heating model can be based on the calibration (e.g., RA measurement) of one or more non-production substrates (e.g., CTC wafers). In some aspects, RA measurement and / or RSD measurement can be performed to determine the temperature of the reticle 300. In some aspects, the online real-time calibration of the reticle heating model can be based on one or more non-production substrates and / or one or more non-production batches. In some aspects, the reticle heating model can be evaluated for each RA measurement between the reticle 300 and multiple non-production substrates in a non-production batch.

[0150] In step 1014, as Figure 3A , Figure 3B , Figure 5 and Figure 6As shown in the example of, a production substrate is processed (e.g., manufactured) by exposing the mask 300 and the production substrate to a dose of radiation based on a mask heating model. In some aspects, RA measurements and / or RSD measurements can be performed to determine the temperature of the mask 300. In some aspects, the online real-time calibration of the mask heating model can be based on one or more production substrates and / or one or more production batches. In some aspects, the mask heating model can be evaluated for each RA measurement between the mask 300 and multiple production substrates in a production batch.

[0151] The above techniques allow for the determination of mask heating calibration (RHC) data. The RHC data provides information on how the mask is heated from a cold state. The RHC data can be used to improve the accuracy of the estimation of the distortion of the mask that depends on RA measurements.

[0152] Figure 5 and Figure 6 Shows an adjustment phase, a calibration phase, and a processing phase. In each of these phases, the temperature of the mask changes within a temperature range. RA measurements can be made at different temperatures of the mask within each temperature range. As described above, a model such as a FEM model can be used to determine the resulting stress and the resulting distortion of the mask. The RHC data can be generated depending on the RA measurements at different temperatures and the corresponding stress and distortion at each temperature. The RHC data thus allows for the determination of how the mask is heated from a cold state and the stress and distortion that occur. The distortion can be determined as a distortion mode, such as the k parameter described earlier.

[0153] According to a first embodiment, the RHC data is used to improve the accuracy of the mask heating model. The mask heating model can include the RHEA described earlier. The RHEA is a modal deformation method, where the modeled deformation depends on RA measurements.

[0154] Figure 11 Shows a deterministic mask heating model. The model includes a RHEA 1101, a mask heating module 1102, and an uncertainty module 1103.

[0155] The input to the RHEA can include a nominal reference state 1104 and RA feedback data 1105. The nominal reference state 1104 is data that describes the initial state of the mask. The nominal reference state 1104 can be obtained from a library. The RA feedback data 1105 can include operating data, such as the dose applied. The RHEA output 1106 can include the heating kinetics determined by the RHEA 1101. The RHEA output 1106 can be provided to the mask heating module 1102.

[0156] The uncertainty module 1103 represents the contribution to the actual distortion of the reticle that cannot be predicted by the deterministic reticle heating module. Specifically, the uncertainty can include events such as timing changes or changes that result in different boundary conditions.

[0157] The reticle heating module 1102 can determine and output a determined modal shape of the reticle distortion. Process corrections for changing the operation of the lithographic apparatus can be determined depending on the output of the reticle heating model to at least partially compensate for the reticle distortion.

[0158] Regarding Figure 11 The problem with the reticle heating model in is that the accuracy of the model depends on the reference state 1104 that describes the initial state of the reticle. The reference state 1104 assumes that the reticle is perfectly adjusted. Thus, if the reticle is not perfectly adjusted, the accuracy of the reticle heating model can be substantially reduced.

[0159] The actual arrival temperature of the reticle depends on the history of the reticle and can vary between about 20 °C and 24 °C. For example, if the reticle is transferred from outside the lithographic apparatus, the reticle temperature will depend on the temperature within the manufacturing facility. If the reticle is provided by the reticle stage, the reticle temperature will depend on the number of exposure processes that have been performed using the reticle, and the dose of the exposure process. If the reticle is provided from a thermal conditioning bath, the reticle temperature will depend on the type of thermal conditioning bath and the length of time the reticle has been in the conditioning bath.

[0160] Thus, the operator of the lithographic apparatus is faced with the choice of either reducing the overlay performance by using a reticle that is not properly adjusted, or slowing down the operation of the lithographic apparatus to allow for proper adjustment of all the reticles used.

[0161] According to a first embodiment, the above problem is solved by providing a reticle heating model that can determine the distortion of the reticle with improved accuracy when the reticle is not perfectly adjusted.

[0162] Figure 12 Shows a new deterministic reticle heating model according to this embodiment. The model according to this embodiment improves the model shown in by applying calibration to the nominal reference state 1104. The applied calibration improves the accuracy of the model by at least partially reducing the effect of the variable initial temperature of the reticle. Figure 11 The model includes a RHEA 1203, a reticle reference module (RRM) 1202, and a reference mask (RM) module 1201.

[0163]

[0164] ​The RRM input 1206 may include a nominal reference state. The input nominal reference state that can be obtained from the library may be the same as the reference state 1104 described earlier, which is the nominal data describing the initial state of the reticle.

[0165] The RRM input 1206 may also include the RHC data described earlier.

[0166] The RRM input 1206 may also include the reticle transfer data received from the reticle transfer device 402. The reticle transfer data may include data on how to transfer the reticle. The reticle transfer data may include location data describing the locations where the reticle has been. The reticle transfer data may include time data describing how long the reticle has been at each location. The reticle transfer data may include thermal data describing the temperature at each location where the reticle has been. The reticle transfer data may include data on the thermal properties of the reticle at each location.

[0167] The RRM input 1206 may also include the current and / or previous outputs from the RHEA 1203, as well as other data.

[0168] The RRM 1202 may receive updated inputs for each batch substrate being processed and / or whenever an event occurs in the reticle transfer device 402.

[0169] The RRM output 1210 may be the data received by the RRM 1202, or data generated depending on the data received by the RRM 1202. The RRM output 1210 may be an input to the RM 1201. The RRM 1202 may provide the RRM output 1210 during the first RA measurement using the reticle for each use of the reticle.

[0170] The RM input 1204 may also include RA measurement data and exposure data. The RM input 1204 may be provided to the RM 1201 during the first RA measurement using the reticle for each use of the reticle.

[0171] The RM 1201 may generate a calibrated reference state 1205 depending on the data received by the RM 1201. The calibrated reference state is the determination of the shape and properties of the reticle when the reticle is in a cold state. The RM output 1205 includes the calibrated reference state. The RM 1201 may provide the RM output 1205 during the first RA measurement using the reticle for each use of the reticle.

[0172] The RHEA 1203 may receive the RM output 1205 as an input.

[0173] A communication path 1208 may also exist between the RHEA 1203 and the RRM 1202. The communication path may utilize the communication of operation data, such as whether a timing anomaly (hiccup) or other processing delay has occurred.

[0174] The RHEA input 1204 may also include RA measurement data and exposure data. After each RA measurement and / or exposure process is performed, the RHEA input 1204 may be provided to the RHEA 1203.

[0175] The RHEA may also receive RA feedback data 1209. The RA feedback data 1209 may be provided to the RHEA 1203 for each batch substrate being processed and / or whenever an event occurs in the reticle transfer device 402. The RA feedback data 1209 may be the same as the RA feedback data described earlier with reference to Figure 11 that described.

[0176] The RHEA 1203 may use the received inputs to determine heating kinetics. Specifically, the RHEA 1203 may rely on the determination of the shape of the reticle when the reticle is in a cold state, the current temperature of the reticle (which may be estimated based on RA measurements), and data on how the shape of the reticle changes as the reticle is heated from its cold state to its current temperature (provided by the RHC data) to determine the current shape of the reticle. The RHEA 1203 may thus perform a more accurate determination at a given current temperature of the reticle than techniques that are based only on the nominal reference state 1104 without any calibration.

[0177] The RHEA output 1207 may include heating kinetics that may be input to the reticle heating module 1102 for determining and outputting a mode shape, which is the determination of the deformation of the reticle, as described earlier with reference to Figure 11 that described. Alternatively, there may be no reticle heating module 1102, and the RHEA output 1207 may include the determination of a mode shape that is the determination of the deformation of the reticle.

[0178] After each RA measurement and / or exposure process is performed, the RHEA output 1207 may be output from the RHEA 1203.

[0179] The operation of this embodiment is described in more detail below.

[0180] When starting to process a batch of substrates, the temperature of the reticle may be unknown, and the reticle may be in a hot state or a cold state.

[0181] RA measurement can be performed. The RA measurement can be input to RM 1201. RM 1201 can use the data received by RRM 1202 to determine the reference shape data of the reticle. RM 1201 can estimate the reference reticle alignment data as follows:

[0182]

[0183] In the above equation, is the reference reticle alignment data estimated based on the measured and stored reticle shape data. The measured and stored reticle shape data are filtered, as shown by to remove any pre-existing systematic effects on the reticle heating calibration KPIs (such as r4, r18, r10, etc.).

[0184] The calibration process can separate the stress effect from the thermo-mechanical effect of the reticle heating behavior. Thus, the stress-induced effects can be distinguished and reduced. As described earlier with reference to Figure 6 the reticle can be cooled in the conditioning stage during which stress exists in the reticle. Then a stress reduction stage that substantially reduces stress can be performed. Then, in the calibration stage and the processing stage, the substantially stress-free reticle can be heated across a temperature range that substantially overlaps with the temperature range (within which the reticle is cooled during the conditioning stage). The stress effect can be determined based on the comparison of the stressed state and the substantially stress-free state of the reticle. Specifically, a filtering operation can be performed to remove any systematic effects. In the case where represents the conditioning stage and represents the calibration stage and / or the processing stage, the comparison of the stressed state and the substantially stress-free state of the reticle can determine as follows:

[0185]

[0186] can be used to determine the calibrated reference as follows:

[0187]

[0188] The calibrated reference can be used to determine the shape of the reticle in its cold state. This can be used to appropriately model the state of the reticle in its current state, regardless of the variation in the introduction temperature of the reticle.

[0189] Figure 13Shows the difference in the modeled ratio of overlay to reticle temperature when processing a batch of substrates W for both a known model 1302 and a new model 1301 according to this embodiment.

[0190] In Figure 13 , the y-axis represents the modeled ratio of overlay to reticle temperature. The x-axis represents the time for processing a batch of substrates. The known model 1302 does not use the calibrated reference state of the reticle and incorrectly assumes that the reticle is perfectly adjusted. The model 1301 according to this embodiment improves the known model by using a calibrated reference to determine the calibrated reference state 1205. The calibrated reference state 1205 can be used with all substrates in each batch. For each separate batch of substrates, the shape of the reticle in its cold state can be determined, and the current shape of the reticle can be appropriately determined.

[0191] This embodiment improves the accuracy of the modeled state of the reticle. Thus, the process correction applied in response to the modeled reticle deformation is more appropriate, and thus the overlay performance is improved without reducing the productivity of the system. The performance of the model may be less sensitive to temperature changes of the reticle. Therefore, when using a reticle that is not in a perfectly adjusted state, the accuracy of the model is improved. The overlay effect caused by the thermal reticle used can be reduced by about half, and the sensitivity of the system to changes in the applied process correction is reduced. This embodiment does not require a temperature sensor for measuring the temperature of the reticle.

[0192] According to a second embodiment, a technique for improving the accuracy of a reticle heating model when a rapid batch transition occurs is provided.

[0193] The lithography process performed on a substrate may include: using a first reticle on a batch of substrates; using a second reticle on the batch of substrates; and then using the first reticle again on the batch of substrates. This may occur, for example, when a first pattern is required on the first layer of a substrate, a second pattern is required on the second layer of the substrate, and the same first pattern is required again on the third layer of the substrate.

[0194] Before the first use of the first reticle, the first reticle may initially be in a cold state and properly adjusted in the IRL for use. The first reticle may then be heated when it is used in the first lithography process performed on the batch of substrates. Then, the first reticle is not used when performing the lithography process using the second reticle. Therefore, the first reticle cools during this period. Then the first reticle is used again. The time period between the end of the first use of the first reticle and the reuse of the first reticle may not be sufficient for the first reticle to cool to the cold state.

[0195] Figure 14Schematically shows the overlay error that may be caused by the temperature of the reticle without performing a process that does not correct for such overlay error sources. In time period A1, the reticle is used and heated. In time period B, the reticle is not used and is cooled down. In time period A2, the reticle is used again. Figure 14 Illustrates that when time period B is short, the reticle cannot be cooled to the same cold state as at the start of time period A1. If the reticle heating model assumes that the reticle is in a cold state at the start of time period A2, the modeled deformation of the reticle will be inaccurate. Therefore, the determined process correction for compensating for the heating of the reticle will also be inaccurate. This can be referred to as the ABA batch sequence problem, or the rapid loss of transition problem.

[0196] This embodiment provides a technique for determining when a rapid batch transition occurs. This technique can be used to improve the accuracy of the reticle heating model.

[0197] According to this embodiment, the conveyance of the reticle is tracked and the conveyance of the reticle is used to generate reticle conveyance data. The reticle conveyance data includes data on each location where the reticle has been, and the time of the reticle at each location. A determination as to whether a rapid batch transition has occurred is made depending on the reticle conveyance data and the known thermal properties of the reticle. Then a decision on how to configure the reticle heating model can be made depending on whether a rapid batch transition has occurred.

[0198] When the reticle is first loaded onto the reticle stage, the reticle heating model is initialized based on the assumption that the reticle is in a cold state. The cold state is the state of the reticle that has been appropriately improved by IRL. The initialization of the reticle heating model can include setting reference data based on the first reticle alignment measurement of the substrates in the batch. The reference data can include, for example, the nominal reference state 1104 described for the first embodiment. All states of the model can be initialized to zero or other default values for when the reticle is in its cold state.

[0199] When processing the first batch of substrates, the state of the reticle heating model is updated to model the heating of the reticle that has occurred and the resulting deformation.

[0200] After the first batch of substrates has been processed, a batch transition process may occur. All states of the reticle heating model at the end of the processing of the first batch of substrates are saved. Then the lithography process can be performed using a different reticle, or the lithography process may not be performed.

[0201] For each reticle that can be used in a lithography process to be performed, reticle transfer data can be generated. The reticle transfer data can include data on how to transfer the reticle. The reticle transfer data can include site data describing the sites where the reticle has been. The reticle transfer data can include time data describing how long the reticle has been at each site. The time data can also include data on the times of each start and end in the lithography process performed using the reticle and the times of the start and end of any other related processes. The reticle transfer data can include thermal data describing the temperature at each site where the reticle has been. The reticle transfer data can include data on the thermal properties of the reticle at each site. The reticle transfer data in this embodiment can be the same as the reticle transfer data generated and used in the first embodiment.

[0202] According to this embodiment, at the start of the process of reusing each reticle, a determination of adjustments to the reticle is made relying on the reticle transfer data. Specifically, an estimate of the temperature of the reticle can be made relying on the reticle transfer data. If the estimated temperature is at or above a threshold, a determination is made that the reticle is in a hot state. A determination that the reticle is in a hot state can be equivalent to a determination that a rapid batch transition has occurred. If the estimated temperature is below the threshold, a determination is made that the reticle is in a cold state. A determination that the reticle is in a cold state can be equivalent to a determination that a rapid batch transition has not occurred.

[0203] If the reticle is determined to be in a cold state, the reticle heating model for the process of reusing the reticle is re-initialized for the process performed using the reticle in the cold state. The re-initialization of the reticle heating model can include setting reference data based on the first reticle alignment measurement of the substrates in the batch. The reference data can include, for example, the nominal reference state 1104 described for the first embodiment. All states of the model can be initialized to zero or other default values for when the reticle is in the cold state.

[0204] If instead the reticle is determined to be in a hot state, the reticle heating model for the process of reusing the reticle is alternatively initialized using the earlier saved state of the reticle heating model at the end of the process of processing the previous batch of substrates using the reticle. This thus more appropriately initializes the model given the state of the reticle.

[0205] Advantageously, the reticle transfer data allows the detection of rapid batch transitions (such as an ABA scenario) and provides a more appropriate initialization of the reticle heating model when the loaded reticle at the start of the process is in a hot state rather than a cold state. The techniques of this embodiment can substantially reduce the errors caused by the sensitivity of the reticle heating model to rapid batch transitions. The techniques of the embodiment can be computationally applied and do not reduce the throughput of the lithography apparatus.

[0206] This embodiment can be used with any reticle heating model. This embodiment can be used in combination with the first embodiment. Specifically, the determination of the state of the reticle can be performed by the RRM 1202 that receives reticle transfer data. Thus, the RRM 1202 can be a decision-making module.

[0207] According to a third embodiment, a technique is provided for improving the accuracy of a reticle heating model when a track hiccup occurs.

[0208] A track hiccup can generally be defined as any timing anomaly that can occur during the execution of a lithography process. Examples of track hiccups include any event that causes an unexpected delay in the substrate loading time, a computational failure that delays an indicated operation, and any one of many other unplanned events that can occur.

[0209] The same reticle is used while performing a lithography process on multiple substrates in a batch. A track hiccup can occur during the processing of the batch. It is known that the reticle heating model does not take into account track hiccups. The occurrence of a track hiccup is therefore a source of inaccuracy in the reticle heating model such that the impact of the timing anomaly on the actual thermal state of the reticle is not modeled.

[0210] This embodiment provides a technique for both detecting when a track hiccup occurs and also determining whether it is appropriate to re-initialize the reticle heating model in response to the occurrence of a track hiccup. Such a technique can be used to improve the accuracy of the reticle heating model.

[0211] According to this embodiment, while the reticle is loaded onto the reticle stage and held clamped to the reticle stage, the process using the reticle is tracked and the process is used to generate reticle process data. The reticle process data includes timing data regarding the exposure process performed using the reticle and any other process while the reticle is clamped to the stage. The reticle heating model can be configured depending on the reticle process data. Specifically, the occurrence and impact of a track hiccup can be determined depending on the reticle process data and the known thermal properties of the reticle. Then the reticle heating model can be configured depending on whether the track hiccup has a substantial impact on the thermal properties of the reticle.

[0212] This embodiment is described in more detail below.

[0213] When the reticle is first loaded onto the reticle stage, the reticle heating model can be initialized based on the assumption that the reticle is in a cold state. The cold state is the state of the reticle that has been appropriately improved by IRL. The initialization of the reticle heating model can include setting reference data based on the first reticle alignment measurement performed on the first substrate in the batch. The reference data can include, for example, the nominal reference state 1104 described for the first embodiment. All states of the reticle heating model can be initialized to zero or other default values for the reticle in the cold state.

[0214] During the processing of the first batch of substrates, the state of the reticle heating model is updated to model the heating of the reticle that has occurred and the resulting deformation.

[0215] Generate reticle process data, which includes timing data regarding the exposure process performed using the reticle, data regarding the dose of each exposure process, and any other process data regarding the properties affecting the reticle while the reticle remains clamped to the reticle stage. The reticle process data can be monitored and used to determine when an orbit timing anomaly has occurred. For example, when the exposure process has not been performed within the expected time window of the exposure process, it can be determined that an orbit timing anomaly has occurred. The determination that an orbit timing anomaly has occurred can also rely on other parts of the overall lithography system. For example, the operation of the substrate transfer device can be relied upon to make the determination that an orbit timing anomaly has occurred.

[0216] When the determination that an orbit timing anomaly has occurred is made, determine the impact of the orbit timing anomaly on the reticle. The duration of the orbit timing anomaly can be known from the reticle process data. The thermal properties of the reticle can also be known. The reticle process data and the known thermal properties of the reticle can be used to determine whether the duration of the orbit timing anomaly is long enough for the temperature of the reticle to change substantially. Specifically, the temperature change of the reticle can be estimated. When the temperature change is at or above the threshold, it can be determined that a long orbit timing anomaly has occurred. When the temperature change is below the threshold, it can be determined that a short orbit timing anomaly has occurred.

[0217] Quickly resume the use of the reticle clamped to the stage after the orbit timing anomaly ends. Then configure the reticle heating model for the reticle depending on whether the determined orbit timing anomaly is a short orbit timing anomaly or a long orbit timing anomaly.

[0218] When the determination that the orbit timing anomaly is a short orbit timing anomaly is made, configure the reticle heating model based on the state of the heating model before the orbit timing anomaly occurred. In other words, the reticle heating model can be substantially unchanged, and the reticle heating model can operate as if no orbit timing anomaly had occurred.

[0219] When it is determined that the out-of-track timing anomaly is a long out-of-track timing anomaly, the reticle heating model can be configured as if the reticle were in the cold state. In other words, the reticle heating model can be reconfigured to the same state as the state used to initialize the reticle heating model when the reticle is first loaded onto the reticle stage. All states of the reticle heating model can be initialized to zero or other default values for the reticle in its cold state.

[0220] Advantageously, this embodiment provides a more appropriate configuration of the reticle heating model when an out-of-track timing anomaly occurs. The techniques of this embodiment can substantially reduce errors caused by the sensitivity of the reticle heating model to changes in reticle temperature due to out-of-track timing anomalies. The techniques of the embodiment can be computationally applied without reducing the throughput of the lithography apparatus.

[0221] This embodiment can be used with any reticle heating model. This embodiment can be used in combination with all other embodiments described throughout this document. Specifically, the determination of whether a long or short out-of-track timing anomaly has occurred can be performed by the RRM 1202. Thus, the RRM 1202 can be a decision-making module. The RRM 1202 can generate reticle processing data or receive reticle processing data from another source. The known thermal properties of the reticle can be stored in the RRM 1202 or provided to the RRM 1202 from an external database.

[0222] According to a fourth embodiment, a new technique for determining and compensating for the effects of the clamping force is provided. The fourth embodiment can be used in combination with the reticle heating model of the first embodiment described throughout this document and / or the techniques of any of the other embodiments.

[0223] As previously described, the reticle is clamped to the reticle stage 200. A problem that can occur is that the clamping force for holding the reticle can change over time. This can be caused by, for example, frictional stresses in the lock between the reticle and the reticle stage 200. A substantial change in the clamping force can occur over a period of about 4 to 8 hours, and if not compensated for, it will increase the overlay error by about 2 nm.

[0224] It is known to compensate for deformation caused by changes in the clamping force by using RA measurements of edge marks and including the measurement data in the reticle heating model. However, this reduces the throughput by about 7 substrates per hour. The inaccuracy in each edge mark measurement also reduces the accuracy of the reticle heating model. Edge mark measurements also degrade the performance of the resist coating on the substrate W.

[0225] Figure 15Shows a reticle 1501. The reticle 1501 is surrounded by horizontally aligned edge marks 1502, 1503 and vertically aligned edge marks 1504, 1505, 1506, 1507. The horizontally aligned edge marks 1502, 1503 include an upper horizontal edge mark 1502 and a lower horizontal edge mark 1503. The vertically aligned edge marks 1504, 1505, 1506, 1507 include a central vertical edge mark 1505, an upper vertical edge mark 1504, a lower vertical edge mark 1507 and a non-central vertical edge mark 1506.

[0226] Figure 16 Shows how to obtain RA measurements for a process performed on a batch of substrates according to the prior art. For the first substrate in the batch, as shown by RA 0, RA measurements are obtained from all the horizontally aligned edge marks 1502, 1503 and the vertically aligned edge marks 1504, 1505, 1506, 1507. For each subsequent substrate in the batch, as shown by RA 1 to RAN, RA measurements are obtained from all the horizontally aligned edge marks 1502, 1503 and at least the central vertical edge mark 1505.

[0227] The RA measurements for each substrate can be provided to a reticle heating model and used to determine the overall deformed shape of the reticle. Specifically, the measurements from the central vertical edge mark 1505 are used to determine the deformation caused by the clamping effect of each substrate.

[0228] Figure 17 Shows an alternative technique for obtaining RA measurements for a process performed on a batch of substrates according to this embodiment. For the first substrate in the batch, as shown by RA 0, RA measurements can be obtained from some or all of the horizontally aligned edge marks 1502, 1503 and the vertically aligned edge marks 1504, 1505, 1506, 1507. For each subsequent substrate in the batch, as shown by RA 1 to RA N, RA measurements are obtained only from some or all of the horizontally aligned edge marks 1502, 1503. Thus, the central vertical edge mark 1505 is measured only for the first substrate and not for subsequent substrates.

[0229] RA measurements for the first substrate can be provided to the reticle heating model and used to determine the overall deformed shape of the reticle, including the effect of the shape of the reticle platform 200 and clamped to the reticle platform 200. The same modeled deformation of the clamping effect is then used for the remaining substrates in the batch. It is suitable to use the same clamping effect model for each substrate in a batch because the time required to process a batch of substrates is typically 5 to 6 minutes, while the clamping effect typically varies over a period of 4 to 8 hours. Thus, the clamping effect remains substantially unchanged when processing a batch of substrates.

[0230] RA measurements can also be used to separately determine the deformation caused by the clamping effect and the reticle-induced deformation (such as due to reticle heating). Then, the systematic drift caused by the clamping effect can be determined and included in the calibration used to improve the accuracy of the modeled deformation.

[0231] Advantageously, this embodiment increases the substrate processing rate due to the need for fewer RA measurements. Additionally, this embodiment avoids the degradation of the resist that occurs when measuring the central vertical edge mark 1505 for each substrate in a batch.

[0232] The RA measurements obtained in this embodiment can be used by the reticle deformation model to determine the deformation caused by the clamping effect. Then, process corrections can be determined depending on the determined deformation to at least partially compensate for the deformation.

[0233] The embodiment includes a reticle deformation model that includes a reticle heating model. Specifically, the RA measurements obtained in this embodiment can be used by the previously described reticle heating model according to any of the other embodiments described herein. The RA measurements of the first substrate in a batch can be used to initialize the reticle heating model.

[0234] According to a fifth embodiment, a new technique is provided for determining the deformation of the reticle shape caused by clamping the reticle using a reticle clamp. The determined deformation can then be at least partially compensated for.

[0235] As previously described, the reticle is fastened to the reticle platform 200 by a reticle clamp. The clamping force applied to the reticle by the reticle clamp can deform the shape of the reticle. The distribution of the clamping force and the resulting deformation of the reticle shape can depend on the shape of the clamping surface.

[0236] The mask deformation caused by the static clamping force can be determined once and then compensated. However, a possible problem is that the clamping force maintaining the mask is not static. In other words, the clamping force can vary over time, and the resulting deformation of the mask shape can thus vary over time. The time variation of the clamping force may be caused by, for example, the frictional stress of the lock between the mask and the mask platform 200. A substantial change in the clamping force may occur within a period of about 4 to 8 hours, and if not compensated, it will increase the overlay error by about 2 nm.

[0237] Due to the time variation of the mask deformation caused by the clamping force, the known techniques frequently measure the overall mask deformation so that the mask deformation can be compensated. Specifically, the known techniques obtain the RA measurement and the edge mark measurement of the mask for each substrate being processed using the mask. The RA measurement and the edge mark measurement are then used to model the deformation of each substrate. Then an application correction is applied to compensate for the determined deformation.

[0238] The problem with the known techniques is that the time required to obtain the RA measurement and the edge mark measurement will reduce the overall productivity of the lithography system. Any inaccuracy in each edge mark measurement is also a cause of error. Obtaining the edge mark measurement also degrades the performance of the resist coating of the substrate W.

[0239] In the fourth embodiment, the clamping-induced deformation is determined and provided to the mask heating model. The mask heating model relies on the determined clamping-induced deformation to determine the total mask deformation. The modeled total deformation can then be provided to the deformation-based mask heating controller.

[0240] This embodiment provides a new technique for determining the clamping-induced deformation. Compared with the technique in the fourth embodiment, the determined clamping-induced deformation can be directly provided to the deformation-based mask heating controller. The determined clamping-induced deformation may not be provided to the mask heating model, or may be directly provided to both the deformation-based mask heating controller and the mask heating model.

[0241] In this embodiment, the deformation of the mask caused by the clamping force is determined in a manner that does not require edge mark measurement for each substrate. The overall deformation of the mask can be modeled as a combination of the contributions of different deformation modes to the overall deformation. This embodiment uses one or more previous measurements to determine the deformation modes caused by the clamping force. The determined deformation modes can be used to determine the mask deformation caused by the clamping force and to determine appropriate process corrections to at least partially compensate for the resulting mask deformation. Advantageously, this embodiment increases the production volume due to the need for fewer edge measurements. Other problems experienced by the known techniques can also be avoided or reduced.

[0242] When performing a lithography process for forming features on a substrate, the shape of a mask may be deformed due to both heating effects and the clamping force applied by a mask holder. However, when the mask is properly conditioned and first loaded onto a mask stage, the mask heating effect is substantially not experienced. In other words, when using a mask in a cold state for the first time, the mask heating effect is substantially not experienced. When there is substantially no deformation caused by the mask heating effect, the mask clamping force and the inherent deformation resulting from the cold state of the mask can be the main causes of the overall mask deformation.

[0243] The effect of the overall mask deformation that occurs can be measured based on inspecting the formed features on the substrate. Specifically, it is known that the features formed on the substrate will be inspected by a metrology tool. The metrology tool can be used to determine one or more performance metrics of the lithography process performed on the substrate, such as product overlay error and edge placement error.

[0244] According to this embodiment, the metrology tool is used to determine one or more performance metrics when using a mask in a cold state. Thus, the substantial contributions to the mask deformation measured by the one or more performance metrics are the mask deformation caused by the clamping force and the inherent deformation resulting from the cold state of the mask. The deformation mode of the overall mask deformation can be determined depending on the one or more performance metrics. The deformation mode can be determined by a variety of known techniques, such as PCA analysis, singular value decomposition, and / or other techniques that can be performed by an algorithm.

[0245] The clamping-induced deformation mode can be determined depending on the determined deformation mode from the one or more performance metrics and the predetermined knowledge of the inherent deformation mode present in the cold state of the mask. The inherent deformation mode present in the cold state of the mask can be obtained from a library. The inherent deformation mode present in the cold state of the mask can include data on the expected shape and / or deformation of the mask when the mask is not clamped, and the mask has been properly temperature-conditioned so that it is in a cold state.

[0246] The determination of the clamping-induced deformation allows predicting the overall deformation resulting from using a mask in a cold state before performing a lithography process using the mask. The overall deformation can be predicted depending on the previously determined clamping-induced deformation and the knowledge of the cold state of the mask to be used. Then, a process correction can be performed to at least partially compensate for the predicted overall deformation. The determination and application of the process correction can be performed online.

[0247] Measurements relying on multiple masks (each mask in a cold state) can be used to determine the chucking-induced deformation pattern. Specifically, when processing multiple batches of substrates, the first use of the mask in each batch can be the use of a mask in a cold state. For each use of a mask in a cold state, the above techniques can be used to determine the chucking-induced deformation. The prediction of the chucking-induced deformation used can be based on multiple previously determined chucking-induced deformations.

[0248] The chucking-induced deformation pattern that can be determined as described above can be used to calibrate the mask deformation model to include the effects of the mask chuck. The mask deformation model can additionally rely on the expected deformation pattern of the mask in its cold state and / or the mask heating effect to determine the overall deformation of the mask.

[0249] According to this embodiment, when processing a batch of substrates, the determination of the mask deformation due to the chucking effect is based on the chucking-induced deformation pattern that can be obtained as described above. Thus, the chucking-induced deformation is calculated relying on one or more previously used masks in a cold state. It is suitable to use the same most recently determined chucking-induced deformation for the entire batch of substrates because the processing time for a batch can be a few minutes, while a substantial change in the chucking force may take 4 to 8 hours.

[0250] The determined overall deformation of the mask can then be used to determine process corrections to at least partially compensate for the overall deformation of the mask. The determined overall deformation of the mask can include all of the determination of the heating-induced mask deformation, the expected deformation of the mask in a cold state, and the determination of the deformation caused by the chucking force.

[0251] Advantageously, this embodiment provides a model with a pattern-based determination of the chucking effect on the mask. The techniques of the embodiment can be applied online to predict changes in the deformation of the mask. The embodiment avoids the need for online edge mark measurements for each substrate in a batch. Since the model is pattern-based, the modal deformation shape can be tuned based on the specific properties of the mask and / or the mask chuck and / or the way the mask and / or the mask chuck are used. For example, the modal deformation model can be applied to different mask layouts. The density of the deformation measurements can also vary, as may be suitable for tuning the determination of the parameters used to correct the deformation.

[0252] This embodiment also allows for changes and drifts in the chucking force to be measured and monitored. This provides useful performance information about the mask chuck.

[0253] The techniques of this embodiment can be used in combination with one or more of the techniques in the previous embodiments. Specifically, this embodiment can be used together with the techniques of the fourth embodiment.

[0254] Figure 18 It is a flowchart of the method according to the first embodiment.

[0255] In step 1801, the method starts.

[0256] In step 1803, initial reference shape data representing the shape of the mask is obtained.

[0257] In step 1805, mask heating calibration RHC data including mask shape data and corresponding mask alignment RA measurement data is obtained at different mask temperatures.

[0258] In step 1807, calibrated reference shape data is generated depending on the initial reference shape data, RHC data, and RA measurement.

[0259] In step 1809, the shape and / or deformation of the mask is modeled depending on the calibrated reference shape data.

[0260] In step 1811, the operation of the lithography process using the mask is controlled depending on the modeled shape and / or deformation.

[0261] In step 1813, the method ends.

[0262] Figure 19 It is a flowchart of the method according to the second embodiment.

[0263] In step 1901, the method starts.

[0264] In step 1903, when the mask is used for the lithography process performed on the first batch of substrates, the mask heating model is initialized depending on the reference data of the mask in the cold state and the first mask alignment measurement of the mask.

[0265] In step 1905, the state of the mask heating model is updated when the lithography process is performed on the first batch of substrates.

[0266] In step 1907, the current state of the mask heating model is stored after the lithography process has been performed on the first batch of substrates.

[0267] In step 1909, mask transfer data is generated depending on the transfer of the mask.

[0268] In step 1911, a determination is made as to whether the mask is in the hot state or the cold state depending on the mask transfer data and before the mask is used in the lithography process performed on the second batch of substrates.

[0269] In step 1913, the operation of the lithography process using the mask is controlled depending on the modeled shape and / or deformation.

[0270] In step 1915, the method ends.

[0271] Figure 20 is a flowchart of a method according to a third embodiment.

[0272] In step 2001, the method starts.

[0273] In step 2003, when the mask is used in a lithography process performed on a batch of substrates, a mask heating model is initialized depending on reference data of the mask in a cold state and first mask alignment measurements of the mask.

[0274] In step 2005, the state of the mask heating model is updated when performing a lithography process on the batch of substrates.

[0275] In step 2007, mask process data is generated.

[0276] In step 2009, a determination is made that a long track timing anomaly has occurred depending on the mask process data and known thermal properties of the mask.

[0277] In step 2011, in response to determining that a long track timing anomaly has occurred, the mask heating model is reconfigured to the same state initialization state used when starting to perform a lithography process on the batch of substrates.

[0278] In step 2013, the operation of the lithography process using the mask is controlled depending on the modeled shape and / or deformation.

[0279] In step 2015, the method ends.

[0280] Figure 21 is a flowchart of a method according to a fourth embodiment.

[0281] In step 2101, the method starts.

[0282] In step 2103, before performing a lithography process on a first substrate in a batch of substrates, mask alignment RA measurements are performed using a first plurality of edge marks of the mask, wherein the plurality of edge marks are arranged on a first pair of parallel edges of the mask.

[0283] In step 2105, before performing a lithography process on the first substrate, RA measurements are performed using a second plurality of edge marks of the mask, wherein the plurality of edge marks are arranged on a second pair of parallel edges of the mask and the first pair of parallel edges is orthogonal to the second pair of parallel edges.

[0284] In step 2107, a determination of the shape and / or deformation of a reticle is made by a reticle deformation model that depends on RA measurements of a first plurality of edge marks and a second plurality of edge marks, such that a lithography process performed on a first substrate is controlled depending on the determined shape and / or deformation.

[0285] In step 2109, additional RA measurements are performed using only the first plurality of edge marks before performing a lithography process on a second substrate of the batch of substrates.

[0286] In step 2111, a reticle deformation model determines the deformation of the reticle when performing a lithography process on the second substrate, depending on both the additional RA measurements and the RA measurements obtained before performing the lithography process on the first substrate.

[0287] In step 2113, the operation of a lithography process using the reticle is controlled depending on the modeled shape and / or deformation.

[0288] In step 2115, the method ends.

[0289] Figure 22 is a flowchart of a method according to a fifth embodiment.

[0290] In step 2201, the method starts.

[0291] In step 2203, a lithography process is performed on a first substrate using a reticle in a cold state.

[0292] In step 2205, one or more performance metrics of the lithography process are determined depending on an inspection of the first substrate.

[0293] In step 2207, a deformation mode caused by clamping of the reticle is determined depending on one or more performance metrics.

[0294] In step 2209, a process correction for a lithography process performed on a second substrate is determined and applied depending on the determined deformation mode caused by clamping.

[0295] In step 2211, the method ends.

[0296] Embodiments include multiple modifications and variations of the above technologies.

[0297] In all of the above first to fifth embodiments, the reticle may be the reticle 300 Figures 1 to 10 described. Embodiments also include different types of reticles in use.

[0298] In all of the above first to fifth embodiments, the reticle chuck may be the reference Figures 1 to 10The described fixture 250. The embodiments also include different types of reticle fixtures in use.

[0299] In all of the above first to fifth embodiments, the reticle stage can be the reticle stage 200 described in the reference Figures 1 to 10 The embodiments also include different types of reticle stages in use.

[0300] In all of the above first to fifth embodiments, the reticle transfer device can be the reticle transfer device 402 described in the reference Figures 1 to 10 The embodiments also include different types of reticle transfer devices in use.

[0301] In all of the above first to fifth embodiments, the substrate can be the substrate W described in the reference Figures 1 to 10 The embodiments also include different types of substrates in use.

[0302] In all of the above first to fifth embodiments, the lithography system can be the lithography system described in the reference Figures 1 to 10 The embodiments also include different types of lithography systems in use.

[0303] In the first embodiment, the RRM 1202 and the RM 1201 are separate modules. The embodiments also include a single module that performs the tasks of both the RRM 1202 and the RM 1201.

[0304] The embodiments can be used with any type of lithography system. For example, the lithography system can be an EUV system or a DUV system. The lithography system can be of any design and is not limited to Figures 1 to 2B the specific type of system shown therein.

[0305] In all embodiments, the described determination can be performed by an algorithm implemented in a computer system. The computer system can also determine and apply process corrections for controlling the operation of the lithography system depending on the determination.

[0306] Although specific reference may be made in this text to the use of a lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described in this text may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, LCDs, thin film magnetic heads, etc. Those skilled in the art will appreciate that, in the context of these alternative applications, any use of the terms "wafer" or "die" in this text may be considered synonymous with the more general terms "substrate" or "target portion" respectively. The substrates referred to in this text may be processed in, for example, a track unit (a tool that typically applies a resist layer to a substrate and develops the exposed resist), a metrology unit, and / or an inspection unit, either before or after exposure. Where applicable, the disclosures in this text may be applied to these and other substrate processing tools. In addition, the substrate may be processed more than once, for example to produce a multi-layer IC, such that the term substrate as used in this text may also refer to a substrate that already includes multiple processed layers.

[0307] Although the above may have specifically referred to the use of aspects in the context of optical lithography, it should be understood that the aspects may be used in other applications (e.g., imprint lithography), and are not limited to optical lithography where the context permits. In imprint lithography, the topography in the patterning device defines the pattern formed on the substrate. The topography of the patterning device may be pressed into a resist layer supplied to the substrate, where the resist is cured by the application of electromagnetic radiation, heat, pressure, or a combination thereof. After the resist is cured, the patterning device is removed from the resist, leaving a pattern therein.

[0308] It should be understood that the wording or terminology in this text is for descriptive purposes and not for limiting purposes, such that the terminology or wording of this specification should be interpreted by those skilled in the relevant art in light of the teachings in this text.

[0309] The term "substrate" as used in this text describes a material onto which material layers are added. In some aspects, the substrate itself may be patterned, and the material added on top of the substrate may also be patterned, or the material may remain unpatterned.

[0310] The following examples illustrate rather than limit aspects of the present disclosure. Other suitable modifications and adaptations of the various conditions and parameters commonly encountered in the art that will be apparent to those skilled in the relevant art are within the spirit and scope of the present disclosure.

[0311] Although reference may be made specifically herein to the use of apparatus and / or systems in IC manufacture, it should be clearly understood that such apparatus and / or systems have many other possible applications. For example, it can be used in the manufacture of integrated optical systems, guiding and detecting patterns for magnetic domain memories, LCD panels, thin film magnetic heads, etc. Those skilled in the art will appreciate that in the context of these alternative applications, any use of the terms "reticle", "wafer" or "die" herein should be recognized as being replaced respectively by the more general terms "mask", "substrate" and "target portion".

[0312] Although specific aspects have been described above, it should be understood that the aspects may be practiced in other ways different from those described. The description is not intended to limit the scope of the claimed invention.

[0313] It should be understood that the detailed description section, rather than the summary of the invention and abstract sections, is intended to be used to interpret the scope of the claimed invention. The summary of the invention and abstract sections may set forth one or more, but not all, exemplary aspects contemplated by the inventors and are therefore not intended to limit the aspects and the scope of the appended claims in any way.

[0314] Aspects have been described above with reference to functional building blocks that implement the functions and the relationships of the functions. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined herein. Alternative boundaries may be defined as long as the specified functions and the relationships of the functions are properly implemented.

[0315] The foregoing description of specific aspects will thus fully disclose the general nature of the aspects: Others can readily modify and / or adapt these specific aspects for various applications without undue experimentation by applying the knowledge known to those skilled in the relevant art without departing from the general concept of the aspects. Accordingly, these adaptations and modifications are intended to be within the meaning and scope of the equivalents of the disclosed aspects based on the teachings and guidance presented herein.

[0316] The embodiments include the following first set of numbered aspects:

[0317] 1. A computer system, the computer system being configured to:

[0318] model the shape and / or deformation of a reticle; and

[0319] control the operation of a lithography process using the reticle depending on the modeled shape and / or deformation;

[0320] wherein, in order to model the shape and / or deformation of the reticle, the computer system is configured to:

[0321] obtain initial reference shape data representing the shape of the reticle;

[0322] Obtain reticle heating calibration (RHC) data including reticle shape data and corresponding reticle alignment i.e., RA measurement data at different reticle temperatures;

[0323] Generate calibrated reference shape data depending on initial reference shape data, RHC data, and RA measurements; and

[0324] Model the shape and / or deformation of the reticle depending on the calibrated reference shape data.

[0325] 2. The computer system according to aspect A1, wherein, to generate the RHC data, the computer system is configured to:

[0326] Obtain a first data set including reticle shape data and corresponding RA measurement data at different reticle temperatures as the temperature of the reticle decreases during a first time period;

[0327] Obtain a second data set including reticle shape data and corresponding RA measurement data at different reticle temperatures as the temperature of the reticle increases during a second time period, wherein the second time period is after the first time period, and a process for reducing stress in the reticle is performed between the first time period and the second time period; and

[0328] Generate the RHC data depending on the first data set and the second data set.

[0329] 3. The computer system according to aspect A2, wherein the computer system is configured to determine the RHC data depending on a comparison of the first data set and the second data set.

[0330] 4. The computer system according to any one of aspects A1 to A3, wherein the calibrated reference shape data depends on a determination of the shape of the reticle when the reticle is in a cold state.

[0331] 5. The computer system according to any one of aspects A1 to A4, wherein the calibrated reference shape data depends on a determination of the shape of the reticle when the reticle has been heated from the cold state of the reticle to its current temperature.

[0332] 6. The computer system according to any one of aspects A1 to A5, wherein the calibrated reference shape data depends on a determination of the stress reduction state of the reticle.

[0333] 7. A method, comprising:

[0334] Model the shape and / or distortion of a mask; and

[0335] Control the operation of a lithography process using the mask depending on the modeled shape and / or distortion;

[0336] wherein modeling the shape and / or distortion of the mask comprises:

[0337] Obtain initial reference shape data representing the shape of the mask;

[0338] Obtain mask heating calibration (RHC) data including mask shape data and corresponding mask alignment (RA) measurement data at different mask temperatures;

[0339] Generate calibrated reference shape data depending on the initial reference shape data, the RHC data, and the RA measurements; and

[0340] Model the shape and / or distortion of the mask depending on the calibrated reference shape data.

[0341] 8. The method according to aspect A7, further comprising generating the RHC data by:

[0342] Obtain a first data set including mask shape data and corresponding RA measurement data at different mask temperatures as the temperature of the mask decreases during a first time period;

[0343] Obtain a second data set including mask shape data and corresponding RA measurement data at different mask temperatures as the temperature of the mask increases during a second time period, wherein the second time period is after the first time period and a process for reducing stress in the mask is performed between the first time period and the second time period; and

[0344] Generate the RHC data depending on the first data set and the second data set.

[0345] 9. The method according to aspect A8, wherein the RHC data is determined depending on a comparison of the first data set and the second data set.

[0346] 10. The method according to any one of aspects A7 to A9, wherein the calibrated reference shape data depends on determining the shape of the mask when the mask is in a cold state.

[0347] 11. A method according to any one of aspects A7 to A10, wherein the calibrated reference shape data depends on the determination of the shape of the mask when the mask has been heated from its cold state to its current temperature.

[0348] 12. A method according to any one of aspects A7 to A11, wherein the calibrated reference shape data depends on the determination of the stress-reduced state of the mask.

[0349] 13. A system, comprising:

[0350] A computer system according to any one of aspects A1 to A6; and

[0351] A lithographic apparatus;

[0352] wherein the computer system is configured to control the operation of the lithographic apparatus.

[0353] 14. A device manufacturing method using a lithography process, the device manufacturing method comprising the method according to any one of aspects A7 to A12.

[0354] 15. A non-transitory computer-readable medium program, comprising computer-readable instructions configured to cause a processor to control a lithographic apparatus according to the method according to any one of aspects A7 to A12.

[0355] Embodiments include the following second set of numbered aspects:

[0356] 1. A computer system configured to use a mask heating model to determine the shape and / or deformation of a mask; and

[0357] Control the operation of a lithography process using the mask depending on the modeled shape and / or deformation;

[0358] wherein the computer system is configured to:

[0359] When the mask is used for a lithography process performed on a first batch of substrates, initialize the mask heating model depending on reference data of the mask in a cold state and a first mask alignment measurement of the mask;

[0360] Update the state of the mask heating model when performing the lithography process on the first batch of substrates;

[0361] Store the current state of the mask heating model after performing the lithography process on the first batch of substrates;

[0362] Generate mask transfer data depending on the transfer of the mask;

[0363] Determine whether the mask is in a hot state or a cold state before delivering data dependent on the mask and before using the mask in a lithography process performed on a second batch of substrates;

[0364] If it is determined that the mask is in the hot state, configure an initial state of the mask heating model for the lithography process performed on the second batch of substrates depending on a stored state of the mask heating model; and

[0365] If it is determined that the mask is in the cold state, re-initialize the mask heating model depending on reference data of the mask in the cold state and a first mask alignment measurement of the mask when processing the second batch of substrates.

[0366] 2. The computer system according to aspect B1, wherein the computer system is further configured to determine the mask temperature depending on the mask delivery data.

[0367] 3. The computer system according to aspect B2, wherein the computer system is configured to determine that the mask is in the hot state if a determined mask temperature is higher than a threshold; and

[0368] The computer system is configured to determine that the mask is in the cold state if a determined mask temperature is lower than a threshold.

[0369] 4. The computer system according to any one of aspects B1 to B3, wherein the mask delivery data includes one or more of the following:

[0370] Location data that describes locations where the mask is and has been;

[0371] Time data that describes how long the mask has been in each location and / or when each lithography process in the lithography processes performed using the mask started and ended;

[0372] Thermal data that describes the temperature at each location where the mask has been; and

[0373] Data on thermal properties of the mask at each location.

[0374] 5. The computer system according to any one of aspects B1 to B4, wherein the first batch of substrates includes the same substrates as the second batch of substrates.

[0375] 6. A method, comprising:

[0376] Using a reticle heating model to determine the shape and / or deformation of a reticle; and

[0377] Controlling the operation of a lithography process using the reticle depending on the modeled shape and / or deformation;

[0378] Wherein the method comprises:

[0379] When the reticle is used in a lithography process performed on a first batch of substrates, initializing the reticle heating model depending on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle;

[0380] Updating the state of the reticle heating model when performing the lithography process on the first batch of substrates;

[0381] Storing the current state of the reticle heating model after performing the lithography process on the first batch of substrates;

[0382] Generating reticle transfer data depending on the transfer of the reticle;

[0383] Determining whether the reticle is in a hot state or a cold state depending on the reticle transfer data and before using the reticle in a lithography process performed on a second batch of substrates;

[0384] If it is determined that the reticle is in the hot state, configuring the starting state of the reticle heating model for the lithography process performed on the second batch of substrates depending on the stored state of the reticle heating model; and

[0385] If it is determined that the reticle is in the cold state, re-initializing the reticle heating model depending on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle when processing the second batch of substrates.

[0386] 7. The method according to aspect B6, further comprising determining the reticle temperature depending on the reticle transfer data.

[0387] 8. The method according to aspect B7, wherein the reticle is determined to be in the hot state if the determined reticle temperature is higher than a threshold; and

[0388] The reticle is determined to be in the cold state if the determined reticle temperature is lower than a threshold.

[0389] 9. The method according to any one of aspects B6 to B8, wherein the reticle transfer data comprises one or more of the following:

[0390] Site data that describes the sites where the mask is and has been located;

[0391] Time data that describes how long the mask has been at each site and / or when each lithography process in a lithography process performed using the mask started and ended;

[0392] Thermal data that describes the temperature at each site where the mask has been; and

[0393] Data on the thermal properties of the mask at each site.

[0394] 10. The method according to any one of aspects B6 to B9, wherein the first batch of substrates comprises the same substrates as the second batch of substrates.

[0395] 11. A system comprising:

[0396] A computer system according to any one of aspects B1 to B5; and

[0397] A lithography apparatus;

[0398] wherein the computer system is configured to control the operation of the lithography apparatus.

[0399] 12. A device manufacturing method using a lithography process, the device manufacturing method comprising the method according to any one of aspects B6 to B10.

[0400] 13. A non-transitory computer-readable medium program comprising computer-readable instructions configured to cause a processor to control a lithography apparatus according to the method according to any one of aspects B6 to B10.

[0401] Embodiments include the following third set of numbered aspects:

[0402] 1. A computer system configured to:

[0403] Use a mask heating model to determine the shape and / or deformation of a mask; and

[0404] Control the operation of a lithography process using the mask depending on the modeled shape and / or deformation;

[0405] wherein the computer system is configured to:

[0406] When the mask is used in a lithography process performed on a batch of substrates, initialize the mask heating model depending on reference data of the mask in a cold state and a first mask alignment measurement of the mask;

[0407] Update the state of the reticle heating model when performing the lithography process on the batch of substrates;

[0408] Generate reticle process data;

[0409] Determine that a long-track timing anomaly has occurred depending on the reticle process data and the known thermal properties of the reticle; and

[0410] In response to determining that a long-track timing anomaly has occurred, reconfigure the reticle heating model to the same state initialization state used when starting to perform the lithography process on the batch of substrates.

[0411] 2. The computer system according to aspect C1, wherein the computer system is configured to:

[0412] Detect whether a track timing anomaly has occurred depending on the reticle process data;

[0413] Determine that a short-track timing anomaly has occurred depending on the reticle process data and the known thermal properties of the reticle; and

[0414] In response to determining that a short-track timing anomaly has occurred, continue to use the reticle heating model based on the state of the reticle heating model when detecting the track timing anomaly.

[0415] 3. The computer system according to aspect C2, wherein the computer system is configured to detect that a track timing anomaly has occurred depending on one or more of the following:

[0416] Determine that the exposure process has not been performed within the expected time window for the exposure process; and / or

[0417] Determine that an unplanned change has occurred in the operation of a part of the lithography system used to perform the lithography process using the reticle.

[0418] 4. The computer system according to any one of aspects C1 to C3, wherein the computer system is configured to determine the temperature of the reticle depending on the reticle process data and the known thermal properties of the reticle;

[0419] Wherein determining that a long-track timing anomaly has occurred depends on the temperature change of the reticle caused by the track timing anomaly being higher than a threshold.

[0420] 5. The computer system according to aspect C4 which is subordinate to aspect C2, wherein determining that a short-track timing anomaly has occurred depends on the temperature change of the reticle caused by the track timing anomaly being less than a threshold.

[0421] 6. The computer system according to any one of aspects C1 to C5, wherein the reticle process data includes one or more of the following:

[0422] Timing data regarding an exposure process performed using the reticle;

[0423] Data regarding the dose of each exposure process; and

[0424] Data regarding any process that affects the properties of the reticle while the reticle remains clamped to the reticle stage.

[0425] 7. The computer system according to any one of aspects C1 to C6, wherein when an orbit timing anomaly occurs, the reticle remains clamped to the reticle stage.

[0426] 8. A method, comprising:

[0427] Using a reticle heating model to determine the shape and / or deformation of the reticle; and

[0428] Controlling the operation of a lithography process using the reticle depending on the modeled shape and / or deformation;

[0429] Wherein the method comprises:

[0430] When the reticle is used in a lithography process performed on a batch of substrates, initializing the reticle heating model depending on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle;

[0431] Updating the state of the reticle heating model when performing the lithography process on the batch of substrates;

[0432] Generating reticle process data;

[0433] Determining that a long orbit timing anomaly has occurred depending on the reticle process data and known thermal properties of the reticle; and

[0434] In response to determining that a long orbit timing anomaly has occurred, reconfiguring the reticle heating model to the same state initialization state used when starting to perform a lithography process on the batch of substrates.

[0435] 9. The method according to aspect C8, further comprising:

[0436] Detecting whether an orbit timing anomaly has occurred depending on the reticle process data;

[0437] Determining that a short orbit timing anomaly has occurred depending on the reticle process data and known thermal properties of the reticle; and

[0438] In response to determining that a short track timing anomaly has occurred, continue to use the reticle heating model based on the state of the reticle heating model when the track timing anomaly is detected.

[0439] 10. The method according to aspect C9, wherein detecting that a track timing anomaly has occurred includes one or more of the following:

[0440] Determining that an exposure process has not been performed within an expected time window for the exposure process; and / or

[0441] Determining that an unplanned change has occurred in the operation of a part of a lithography system that is used to perform a lithography process using the reticle.

[0442] 11. The method according to any one of aspects C8 to C10, further comprising determining the temperature of the reticle depending on reticle process data and known thermal properties of the reticle;

[0443] Wherein determining that a long track timing anomaly has occurred is dependent on a change in the temperature of the reticle caused by the track timing anomaly being above a threshold.

[0444] 12. The method according to aspect C11, which is subordinate to aspect C9, wherein determining that a short track timing anomaly has occurred is dependent on a change in the temperature of the reticle caused by the track timing anomaly being less than a threshold.

[0445] 13. The method according to any one of aspects C8 to C12, wherein the reticle process data includes one or more of the following:

[0446] Timing data regarding an exposure process performed using the reticle;

[0447] Data regarding the dose of each exposure process; and

[0448] Data regarding any process that affects the properties of the reticle while the reticle remains clamped to the reticle platform.

[0449] 14. The method according to any one of aspects C8 to C13, wherein when a track timing anomaly occurs, the reticle remains clamped to the reticle platform.

[0450] 15. A system, comprising:

[0451] A computer system according to any one of aspects C1 to C7; and

[0452] A lithography apparatus;

[0453] Wherein the computer system is configured to control the operation of the lithography apparatus.

[0454] 16. A device manufacturing method using a lithography process, the device manufacturing method comprising the method according to any one of aspects C8 to C13.

[0455] 17. A non - transitory computer - readable medium program comprising computer - readable instructions configured to cause a processor to control a lithography apparatus according to the method according to any one of aspects C8 to C13.

[0456] The embodiments include the following fourth group of numbered aspects:

[0457] 1. A computer system configured to:

[0458] Use a mask deformation model to determine the shape and / or deformation of a mask; and

[0459] Control the operation of a lithography process using the mask depending on the modeled shape and / or deformation;

[0460] Wherein the computer system is configured to:

[0461] Before performing a lithography process on a first substrate in a batch of substrates, perform a mask alignment, i.e., RA measurement, using a first plurality of edge marks of the mask, wherein the plurality of edge marks are arranged on a first pair of parallel edges of the mask;

[0462] Before performing the lithography process on the first substrate, perform an RA measurement using a second plurality of edge marks of the mask, wherein the plurality of edge marks are arranged on a second pair of parallel edges of the mask and the first pair of parallel edges is orthogonal to the second pair of parallel edges;

[0463] Determine the shape and / or deformation of the mask through the mask deformation model depending on the RA measurements of the first plurality of edge marks and the second plurality of edge marks, such that the lithography process performed on the first substrate is controlled depending on the determined shape and / or deformation;

[0464] Before performing a lithography process on a second substrate in the batch of substrates, perform an additional RA measurement using only the first plurality of edge marks; and

[0465] Determine the deformation of the mask when performing the lithography process on the second substrate through the mask deformation model depending on both the additional RA measurement and the RA measurement obtained before performing the lithography process on the first substrate.

[0466] 2. The computer system according to aspect D1, wherein the batch of substrates includes more than two substrates, and the computer system is configured to:

[0467] perform RA measurement only using the first plurality of edge marks between performing lithography processes on two consecutive substrates in the batch of substrates; and

[0468] determine the deformation of the mask during the lithography process for each substrate through the mask deformation model, depending on both the most recently performed RA measurement and the RA measurement obtained before performing the lithography process on the first substrate.

[0469] 3. The computer system according to aspect D1 or D2, wherein the mask deformation model is configured to determine the chuck-induced mask deformation before performing the lithography process on the first substrate; and

[0470] use the same determined chuck-induced mask deformation for all substrates in the batch.

[0471] 4. The computer system according to any one of aspects D1 to D3, wherein the computer system is configured to include the chuck-induced mask deformation in the initial state of the mask heating model.

[0472] 5. A method, comprising:

[0473] using a mask deformation model to determine the shape and / or deformation of a mask; and

[0474] controlling the operation of a lithography process using the mask depending on the modeled shape and / or deformation;

[0475] wherein the method includes:

[0476] performing mask alignment, i.e., RA measurement, using the first plurality of edge marks of the mask before performing a lithography process on a first substrate in a batch of substrates, wherein the plurality of edge marks are arranged on a first pair of parallel edges of the mask;

[0477] performing RA measurement using the second plurality of edge marks of the mask before performing the lithography process on the first substrate, wherein the plurality of edge marks are arranged on a second pair of parallel edges of the mask and the first pair of parallel edges are orthogonal to the second pair of parallel edges;

[0478] determining the shape and / or deformation of the mask through the mask deformation model depending on the RA measurements of the first plurality of edge marks and the second plurality of edge marks, such that the lithography process performed on the first substrate is controlled depending on the determined shape and / or deformation;

[0479] Before performing the lithography process on the second substrate in the batch of substrates, perform additional RA measurements using only the first plurality of edge marks; and

[0480] Based on the mask deformation model, determine the deformation of the mask when performing the lithography process on the second substrate, depending on both the additional RA measurements and the RA measurements obtained before performing the lithography process on the first substrate.

[0481] 6. The method according to aspect D5, wherein the batch of substrates includes more than two substrates, and the method further includes:

[0482] Between performing the lithography process on two consecutive substrates in the batch of substrates, perform RA measurements using only the first plurality of edge marks; and

[0483] Based on the mask deformation model, determine the deformation of the mask when performing the lithography process on each substrate, depending on both the most recently performed RA measurements and the RA measurements obtained before performing the lithography process on the first substrate.

[0484] 7. The method according to aspect D5 or D6, wherein the mask deformation model determines the chuck-induced mask deformation before performing the lithography process on the first substrate; and

[0485] Use the same determined chuck-induced mask deformation for all substrates in the batch.

[0486] 8. The method according to any one of aspects D5 to D7, wherein the method includes: including the chuck-induced mask deformation in the initial state of the mask heating model.

[0487] 9. A system, comprising: a computer system according to any one of aspects D1 to D4; and

[0488] A lithography apparatus;

[0489] wherein the computer system is configured to control the operation of the lithography apparatus.

[0490] 10. A device manufacturing method using a lithography process, the device manufacturing method including the method according to any one of aspects D5 to D8.

[0491] 11. A non-transitory computer-readable medium program, including computer-readable instructions configured to cause a processor to control a lithography apparatus according to the method according to any one of aspects D5 to D8.

[0492] Embodiments include the following fifth group of numbered aspects:

[0493] 1. A computer system, the computer system being configured to:

[0494] Control a lithography process performed on a first substrate using a reticle in a cold state;

[0495] Determine one or more performance metrics of the lithography process depending on an inspection of the first substrate;

[0496] Determine a deformation mode caused by clamping of the reticle depending on one or more performance metrics; and

[0497] Determine and control the application of process correction to a lithography process performed on a second substrate depending on the determined deformation mode caused by clamping.

[0498] 2. The computer system according to aspect E1, wherein the one or more performance metrics are determined depending on a measurement of the nature of features formed on the first substrate by the lithography process.

[0499] 3. The computer system according to aspect E1 or E2, wherein the computer system is configured to determine the deformation mode caused by clamping by:

[0500] Determine a deformation mode of overall reticle deformation depending on the one or more performance metrics;

[0501] Obtain data on an expected deformation mode of the reticle in a cold state when the reticle is not clamped; and

[0502] Determine the deformation mode caused by clamping depending on the determined deformation mode of overall reticle deformation and the expected deformation mode of the reticle in a cold state when the reticle is not clamped.

[0503] 4. The computer system according to any one of aspects E1 to E3, wherein the first substrate and the second substrate are in different batches of substrates.

[0504] 5. The computer system according to any one of aspects E1 to E4, wherein the computer system is configured to determine, for each batch of substrates in a plurality of batches of substrates, a deformation mode caused by clamping of a reticle in a cold state, such that for each batch of substrates, a deformation mode caused by clamping of the reticle used is determined;

[0505] wherein the computer system is configured to determine and control the application of process correction to a lithography process depending on a plurality of determinations of the deformation mode caused by clamping.

[0506] 6. A method, comprising:

[0507] Performing a lithography process on a first substrate using a mask in a cold state;

[0508] Determining one or more performance metrics of the lithography process depending on an inspection of the first substrate;

[0509] Determining a deformation mode caused by clamping of the mask depending on the one or more performance metrics; and

[0510] Determining and applying a process correction for a lithography process performed on a second substrate depending on the determined deformation mode caused by clamping.

[0511] 7. The method according to aspect E6, wherein the one or more performance metrics are determined depending on a measurement of the nature of features formed on the first substrate by the lithography process.

[0512] 8. The method according to aspect E6 or E7, wherein determining the deformation mode caused by clamping includes:

[0513] Determining a deformation mode of overall mask deformation depending on the one or more performance metrics;

[0514] Obtaining data on an expected deformation mode of the mask in a cold state when the mask is not clamped; and

[0515] Determining the deformation mode caused by clamping depending on the determined deformation mode of overall mask deformation and the expected deformation mode of the mask in a cold state when the mask is not clamped.

[0516] 9. The method according to any one of aspects E6 to E8, wherein the first substrate and the second substrate are in different batches of substrates.

[0517] 10. The method according to any one of aspects E6 to E9, further comprising performing the method for each batch of substrates in a plurality of batches of substrates using a mask in a cold state, such that for each batch of substrates, a deformation mode caused by clamping of the used mask is determined;

[0518] wherein a process correction applied to the lithography process is determined depending on a plurality of determinations of the deformation mode caused by clamping.

[0519] 11. A system, comprising:

[0520] A computer system according to any one of aspects E1 to E5; and

[0521] A lithography apparatus;

[0522] wherein a computer system is configured to control the operation of a lithographic apparatus.

[0523] 12. A device manufacturing method using a lithographic process, the device manufacturing method comprising the method according to any one of aspects E6 to E10.

[0524] 13. A non - transitory computer - readable medium program comprising computer - readable instructions configured to cause a processor to control a lithographic apparatus according to the method according to any one of aspects E6 to E10.

[0525] The breadth and scope of these aspects should not be limited by any of the above - mentioned exemplary aspects, but should be defined only in accordance with the following claims for patent and their equivalents.

Claims

1. A computer system, the computer system being configured to: Model the shape and / or deformation of a mask; and Control the operation of a lithography process using the mask depending on the modeled shape and / or deformation; Wherein, in order to model the shape and / or deformation of the mask, the computer system is configured to: Obtain initial reference shape data representing the shape of the mask; Obtain mask heating calibration (RHC) data including mask shape data and corresponding mask alignment (RA) measurement data at different mask temperatures; Generate calibrated reference shape data depending on the initial reference shape data, the RHC data, and the RA measurement; And Model the shape and / or deformation of the mask depending on the calibrated reference shape data.

2. The computer system according to claim 1, wherein, In order to generate the RHC data, the computer system is configured to: Obtain a first data set including mask shape data and corresponding RA measurement data at different mask temperatures as the temperature of the mask decreases during a first time period; Obtain a second data set including mask shape data and corresponding RA measurement data at different mask temperatures as the temperature of the mask increases during a second time period, wherein the second time period is after the first time period, and a process for reducing stress in the mask is performed between the first time period and the second time period; And Generate the RHC data depending on the first data set and the second data set.

3. The computer system according to claim 2, wherein The computer system is configured to determine the RHC data depending on a comparison of the first data set and the second data set.

4. The computer system according to claim 1, wherein, The calibrated reference shape data depends on the determination of the shape of the mask when the mask is in a cold state.

5. The computer system according to claim 1, wherein, The calibrated reference shape data depends on the determination of the shape of the mask when the mask has been heated from the cold state of the mask to its current temperature.

6. The computer system according to claim 1, wherein, The calibrated reference shape data depends on the determination of the stress reduction state of the mask.

7. A method, comprising: Modeling the shape and / or deformation of a mask; And Controlling the operation of a lithography process using the mask depending on the modeled shape and / or deformation; Wherein modeling the shape and / or deformation of the mask comprises: Obtaining initial reference shape data representing the shape of the mask; Obtaining mask heating calibration (RHC) data including mask shape data and corresponding mask alignment (RA) measurement data at different mask temperatures; Generating calibrated reference shape data depending on the initial reference shape data, the RHC data, and the RA measurement; and Modeling the shape and / or deformation of the mask depending on the calibrated reference shape data.

8. The method according to claim 7, further comprising generating the RHC data by: Obtaining a first data set including mask shape data and corresponding RA measurement data at different mask temperatures as the temperature of the mask decreases during a first time period; As the temperature of the mask increases during a second time period, a second data set including mask shape data and corresponding RA measurement data is obtained at different mask temperatures, wherein, the second time period is after the first time period, and a process for reducing stress in the mask is performed between the first time period and the second time period; and the RHC data is generated depending on the first data set and the second data set.

9. The method according to claim 8, wherein The RHC data is determined depending on a comparison of the first data set and the second data set.

10. The method according to claim 7, wherein, The calibrated reference shape data depends on the determination of the shape of the mask when the mask is in a cold state.

11. The method according to claim 7, wherein, The calibrated reference shape data depends on the determination of the shape of the mask when the mask has been heated from the cold state of the mask to its current temperature.

12. The method according to claim 7, wherein The calibrated reference shape data depends on the determination of the stress-reduced state of the mask.

13. A system, comprising: The computer system according to claim 1; and a lithographic apparatus; wherein the computer system is configured to control the operation of the lithographic apparatus.

14. A device manufacturing method using a lithography process, the device manufacturing method comprising the method according to claim 7.

15. A non-transitory computer-readable medium program, comprising computer-readable instructions configured to cause a processor to control a lithographic apparatus according to the method according to claim 7.

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