Method and system for determining reticle deformation

Abstract

A computer system is configured to initialize a reticle heating model in dependence on reference data for a reticle in a cold state and reticle alignment measurements for the reticle. And updating the state of the mask heating model when the photoetching process is performed on the first batch of substrates. And storing the current state of the mask heating model. And generating mask plate transmission data. It is determined that the reticle is in a hot state or a cold state depending on reticle transfer data. In a case where it is determined that the reticle is in the thermal state, an initial state of the reticle heating model is configured depending on the stored state. In a case where it is determined that the reticle is in the cold state, the reticle heating model is reinitialized depending on reference data of the reticle in the cold state and the reticle alignment measurement of the reticle.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application 63 / 435,000, filed on December 23, 2022, and the entire contents of that U.S. application are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to techniques for improving the accuracy of determining deformation of a reticle. Corrections can be determined and applied based on the determined deformation to reduce reticle-induced errors in a lithography process. Background Art

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

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

[0006] A lithographic apparatus may include a reticle stage for holding a patterning device (e.g., a reticle) for transferring 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., focus) and cause deformation of the patterned substrate (e.g., overlay error). A reticle heating model may be used to model and correct for changes in reticle properties. Known reticle heating models rely on a sensor-based approach to calibrate the reticle heating model using a reticle temperature sensor (RTS) and require calibration for batches of production wafers. In some examples, this approach can be inaccurate and inefficient because the RTS may exhibit errors, introducing unnecessary delays and requiring rework of production wafers.

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

[0008] There is a general need to improve known techniques for determining the deformation of a reticle's shape. The determined deformation can be used to determine and process corrections to reduce reticle-induced errors in the lithography process. This can avoid rework of production substrates and / or increase the manufacturing throughput and yield of the lithography process.

[0009] According to a first aspect of the present invention, a computer system is provided, the computer system being configured to determine a shape and / or deformation of a reticle using a reticle heating model; and to control the operation of a lithography process using the reticle in dependence on the modeled shape and / or deformation; wherein the computer system is configured to: initialize the reticle heating model in dependence on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle when the reticle is used for a lithography process performed on a first batch of substrates; update the state of the reticle heating model when the lithography process is performed on the first batch of substrates; store the current state of the reticle heating model after the lithography process has been performed on the first batch of substrates; generating reticle transport data dependent on transport of the reticle; determining, dependent on the reticle transport data and before using the reticle in a lithography process performed on a second batch of substrates, whether the reticle is in the hot state or the cold state; configuring, dependent on the stored state of the reticle heating model, a starting state of the reticle heating model for the lithography process performed on the second batch of substrates if the reticle is determined to be in the hot state; and reinitializing, dependent on the reference data of the reticle in the cold state and the first reticle alignment metrology of the reticle when processing the second batch of substrates if the reticle is determined to be in the cold state.

[0010] According to a second aspect of the present invention, a method is provided, comprising: determining a shape and / or deformation of a mask using a mask heating model; and controlling the operation of a lithography process using the mask in dependence on the modelled shape and / or deformation; wherein the method comprises: initialising the mask heating model in dependence on reference data of a mask in a cold state and a first mask alignment measurement of the mask when the mask is used for a lithography process performed on a first batch of substrates; updating a state of the mask heating model when the lithography process is performed on the first batch of substrates; storing the current state of the mask heating model after the lithography process has been performed on the first batch of substrates; generating a state in dependence on the determining, prior to using the reticle in a lithography process performed on a second batch of substrates, whether the reticle is in the hot state or the cold state, depending on the reticle transport data; configuring, in a case where the reticle is determined to be in the hot state, a 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, in a case where the reticle is determined to be in the cold state, reinitializing the reticle heating model in a case where the reticle is determined to be in the cold state, depending on the reference data of the reticle in the cold state and the first reticle alignment measurement of the reticle, when processing the second batch of substrates.

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

[0012] According to a fourth aspect of the present invention, there is provided a device manufacturing method using a photolithography 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 comprising computer readable instructions configured to cause a processor to control a lithographic apparatus according to the method of the second aspect.

[0014] Implementations of any of the techniques described above may include EUV light sources, DUV light sources, systems, methods, processes, devices, and / or apparatus. Details of one or more implementations are set forth in the accompanying drawings and in the following detailed description. Additional features will be apparent from the description and drawings, as well as from the claims.

[0015] Other features and exemplary aspects of the aspects, as well as the structure and operation of 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 embodiments, further serve to explain the principles of the aspects and to enable one skilled in the relevant art to make and use the aspects.

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

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

[0019] Figure 2B is a schematic diagram of an overall lithography process 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 platform and a reticle according to an exemplary aspect.

[0021] Figure 3B yes Figure 3A Schematic bottom plan view of the reticle platform shown in FIG.

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

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

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

[0025] Figure 7 and Figure 8 According to exemplary aspects, Figure 5 and Figure 6 Schematic diagram of the k parameter of the reticle calibration method shown in FIG.

[0026] Figure 9 and Figure 10 A reticle calibration chart is illustrated according to an exemplary aspect.

[0027] Figure 11 A deterministic reticle heating model is shown.

[0028] Figure 12 A deterministic reticle heating model according to a first embodiment is shown.

[0029] Figure 13The difference in the modeled ratio of overlap to reticle temperature when processing batches of substrates for both the known model and the model according to the first embodiment is shown.

[0030] Figure 14 The overlay error that may be caused by the temperature of the reticle is schematically illustrated if no process is performed that does not correct for this source of overlay error.

[0031] Figure 15 It is shown how RA measurements are obtained for a process performed on the first of a batch of substrates according to known techniques.

[0032] Figure 16 It is shown how RA measurements are obtained for a process performed on a batch of substrates according to known techniques.

[0033] Figure 17 A technique for obtaining RA measurements of a process performed on a batch of substrates according to a fourth embodiment.

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

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

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

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

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

[0039] Features and exemplary aspects of the present invention will become apparent from the detailed description set forth below in conjunction with the accompanying drawings, in which like reference numerals identify corresponding elements throughout. In the drawings, like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. Additionally, typically, the left-most digit of a reference numeral identifies the drawing in which the reference numeral first appears. Unless otherwise indicated, the drawings provided throughout this disclosure should not be construed as being drawn to scale. DETAILED DESCRIPTION

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

[0041] The described aspects and references in this specification to "one aspect," "aspect," "example aspect," "exemplary aspect," etc. indicate that the described aspects may include particular features, structures, or characteristics, but each aspect may not necessarily include the particular features, structures, or characteristics. Furthermore, these phrases do not necessarily refer to the same aspect. Furthermore, when particular features, structures, or characteristics are described in conjunction with an aspect, it should be understood that it is within the knowledge of those skilled in the art to implement such features, structures, or characteristics in conjunction with other aspects, whether or not explicitly described.

[0042] For ease of description, spatially relative terms, such as "below," "lower," "above," "upper," and similar terms, may be used herein to describe the relationship of one element or feature relative to another element or feature illustrated in the drawings. 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 interpreted accordingly.

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

[0044] The term "parasitic thermal effects" as used herein refers to induced or internal stresses and / or deformations of the reticle, such as mechanical stresses and / or deformations due to heating and / or cooling the reticle (e.g., by resistive heating, air 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 batch and is not fabricated into a device (e.g., an IC chip) through a photolithographic process. For example, the non-production substrate can be a chuck temperature conditioning (CTC) wafer or calibration wafer used in a reticle calibration method, such as heating a mold with a calibration reticle and compliant the reticle by exposing the reticle and CTC wafer to a dose of radiation and measuring the reticle alignment and / or reticle temperature.

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

[0047] As used herein, the term "reticle heating model" refers to a modal deformation approach (e.g., analysis of different reticle mode shapes) to determine reticle heating effects based on reticle alignment and / or reticle shape deformation and a finite element model (FEM) (e.g., COMSOL). For example, the reticle heating model can be deterministic (e.g., without random future states) or non-deterministic (e.g., including random future states) of reticle heating effects. Furthermore, the reticle heating model can be considered a reticle heating execution algorithm (RHEA) that uses online modal calibration to determine baseline reticle heating dynamics. The reticle heating model can be calibrated by exposing a reticle and a non-production substrate to a dose of radiation for online, real-time calibration of the reticle heating model. In some aspects, for example, the reticle heating model can be calibrated by exposing a reticle and a production substrate to a dose of radiation for online, real-time calibration of the reticle heating model. Other reticle heating models utilize sensor-based approaches (e.g., using RTS measurements) to calibrate the reticle heating model. This is described in further 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 that can affect the radiation path and cause manufacturing errors (e.g., overlay). Reticle mechanical deformation can be calculated (e.g., based on reticle temperature) and decomposed into k-parameters. Each thermomechanical mode (e.g., eigenvector) can be modeled in real time using modal participation factors μ and time constants τ. The measured overlay and / or alignment can be used to model the associated k-parameter drift, which 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 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 entirety.

[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 reticle heating models. For example, baseline reticle heating dynamics can be analyzed using FEM via finite element analysis. This is described in further detail in U.S. Patent No. 10,429,749, U.S. Patent No. 10,281,825, and U.S. Publication No. 2020 / 0166854, each of which is incorporated herein by reference in its entirety.

[0050] As used herein, the term "key performance indicator" or "KPI" or "k-parameter" refers to the coefficients of a polynomial fitted to the deformation of the 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 distortion (e.g., Figure 7 k4 / my) and k18 indicating barrel deformation in the Y axis (e.g., Figure 8 The k parameter can be used as an input to the lithography process (e.g., lithography apparatus LA, lithocell LC, control system CL) to correct for distortion. This is described in further 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 "inline, real-time calibration" refers to calibration of the reticle heating model during actual fabrication of production substrates. For example, calibration of batches of production substrates can be avoided, and rework of production substrates for calibration purposes can be reduced or avoided. Inline calibration can be performed by exposing the reticle and production substrate to a dose of radiation. Furthermore, calibration can be performed in real time (e.g., at a real-time frame rate or a computation 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, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form that can be read by a machine (e.g., a computing device). For example, machine-readable media may include: read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), etc. In addition, firmware, software, routines, and / or instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are for convenience only and that such actions are actually performed by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc.

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

[0054] Exemplary lithography systems

[0055] Figure 1 A lithographic system is shown comprising a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate and supply a beam of EUV and / or DUV radiation B to the lithographic apparatus LA. The lithographic apparatus LA comprises an illumination system IL, a support structure MT (e.g., mask stage, reticle stage, reticle platform) configured to support a patterning device MA (e.g., mask, 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 the EUV and / or DUV radiation beam B before it is incident on the patterning device MA. In addition, the illumination system IL may include a faceted field mirror arrangement 10 and a faceted pupil mirror arrangement 11. The faceted field mirror arrangement 10 and the faceted pupil mirror arrangement 11 together provide a desired cross-sectional shape and a desired intensity distribution to the EUV and / or DUV radiation beam B. In addition to or as an alternative to the faceted field mirror arrangement 10 and the faceted pupil mirror arrangement 11, the illumination system IL may include other mirrors or arrangements.

[0057] After being adjusted thus, the EUV and / or DUV radiation beam B interacts with the patterning device MA. This interaction may be of the reflective type (as shown), which may be preferred for EUV radiation. This interaction may be of the transmissive type, which may be preferred for DUV radiation. As a result of this interaction, a patterned EUV and / or DUV radiation beam B' is generated. The projection system PS is configured to project the patterned EUV and / or DUV radiation beam B' onto the substrate W. For said purpose, the projection system PS may comprise a plurality of mirrors 13, 14 configured to project the patterned EUV and / or DUV radiation beam B' onto the substrate W held by the substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV and / or DUV radiation beam B', thereby forming an image with features that are smaller than 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 While illustrated in FIG. 1 as having only two mirrors 13 , 14 , the projection system PS may comprise a different number of mirrors (eg six or eight mirrors).

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

[0059] Exemplary Lithography Cell

[0060] Figure 2A A lithography cell LC is shown, which is sometimes also referred to as a lithocell 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 the 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 transport device or robot RO picks up substrates from input / output ports I / O1, I / O2, moves the substrates between different process devices, and transfers the substrates to a feed table LB of the lithography apparatus LA. These devices, often collectively referred to as a track or coating and developing system, are under the control of a track or coating and developing system control unit TCU, which is itself controlled by a management control system SCS, which also controls the lithography apparatus LA via the lithography control unit LACU. Thus, different devices can be operated to maximize throughput and processing efficiency.

[0061] In order to correctly and consistently expose substrates W exposed by the lithographic apparatus LA, it is desirable to inspect the substrates to measure properties of the patterned substrate, such as overlay errors between subsequent layers, line thickness, critical dimensions (CD), and the like. For this purpose, an inspection tool (e.g., a metrology tool MT) may be included in the lithocell LC and / or the lithographic apparatus LA. If errors are detected, adjustments may be made, for example, to the exposure of subsequent substrates or to other processing steps to be performed on the substrate W, particularly if the inspection is performed before other substrates W from the same batch or lot are yet to be exposed or processed.

[0062] An inspection apparatus, which may also be referred to as a metrology apparatus or metrology tool MT, is used to determine properties of a substrate W, and in particular to determine how properties vary between different substrates W or how properties associated with different layers of the same substrate W vary between different layers. The inspection apparatus 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 apparatus may measure properties on a latent image (e.g., an image in a resist layer after exposure), a semi-latent image (e.g., an image in a 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 2B A computer system CL is shown, which is also called a controller or processor. The computer system CL can be part of the lithography cell LC, integrated into the lithography apparatus LA and / or a separate device. The computer system CL is configured to optimize the lithography process, for example, to calibrate the mask heating model. Typically, the patterning process in the lithography apparatus LA is one of the most critical steps in the process, which requires a high degree of accuracy in the dimensioning and placement of the structures on the substrate W. In order to ensure this high accuracy, the computer system CL can be configured to optimize the lithography process, for example, to calibrate the reticle heating model. Figure 2B The three systems are combined in a so-called "holistic" control environment schematically depicted in FIG. Figure 2B As shown in , the “whole” environment may include a lithographic apparatus LA, a computer system CL and a metrology tool MT. For example, the lithographic apparatus LA (first system) may be connected to a computer system CL (second system) and a metrology tool MT (third system).

[0065] The key to this holistic lithography is optimizing the collaboration between these three systems to optimize the lithography process, for example, 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 the 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. Typically, variations in process parameters within the lithography process or patterning process are tolerated within this result.

[0066] The computer system CL may, for example, use a design layout to be patterned (e.g., a portion of a design layout) to predict which resolution enhancement techniques to use and perform computational lithography simulations and calculations, e.g., to determine which mask layouts and lithographic equipment settings achieve the maximum overall process window (in terms of resolution enhancement techniques) for the patterning process. Figure 2B Typically, the resolution enhancement technique is arranged to match the patterning possibilities of the lithographic apparatus LA. The computer system CL may also be used to detect where within the process window the lithographic apparatus LA is currently operating (e.g. using input from the metrology tool MT) to predict whether defects may be present, e.g. due to suboptimal processing (e.g. in the example of FIG. 1 ). Figure 2B is indicated by the arrow pointing to “0” in the second scale SC2).

[0067] The metrology tool MT may provide input to the computer system CL, for example, to enable accurate simulations and predictions. For example, the metrology tool MT may provide alignment information. The metrology tool MT may provide feedback (e.g., via the computer system CL) to the lithographic apparatus LA to identify, for example, possible drift in the calibration state of the lithographic apparatus LA (e.g., in the case of a change in the calibration state of the lithographic apparatus LA). Figure 2B (Indicated by the multiple arrows in the third scale SC3 in the figure). During the lithographic 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 related to the lithographic apparatus LA, the substrate to be patterned W, and / or the reticle 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 entirety.

[0068] Exemplary Reticle Platforms and Reticles

[0069] Figure 3A and Figure 3B A schematic diagram of a reticle platform 200 is shown, according to an exemplary aspect. Figure 3A is a schematic bottom perspective view of reticle platform 200 and reticle 300 according to example aspects. Figure 3B yes Figure 3A Schematic bottom plan view of reticle platform 200 and reticle 300 is shown in FIG.

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

[0071] In some lithographic apparatuses, such as lithographic apparatus LA, a reticle stage 200 having a clamp 250 can be used to hold and position a reticle 300 for scanning or patterning operations. Figure 3A and Figure 3B As shown in FIG, , 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 transverse direction (i.e., the X direction). Furthermore, 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] like Figure 3A and Figure 3B As shown in FIG, the mask 300 may include a mask front side 302, an alignment mark 310, and / or an edge alignment mark 320. The alignment mark 310 is configured to measure the mask alignment between the mask 300 and a substrate (e.g., substrate W, non-production substrate, production substrate). In some aspects, as shown in FIG. Figure 3A and Figure 3BAs shown in FIG, one or more alignment marks 310 may be provided in the corners and / or center of the mask 300 for RA measurement. The edge alignment mark 320 is configured to measure the mask shape deformation of the mask 300 due to thermal expansion when the mask 300 is not within a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, as Figure 3A and Figure 3B As shown in FIG, one or more edge alignment marks 320 can 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 the RSD measurement can be converted to the reticle temperature, for example, by an FEM that solves for the temperature based on the reticle alignment and / or reticle deformation.

[0073] Exemplary Reticle Exchange Equipment

[0074] Figure 4A and Figure 4B A schematic diagram of a reticle exchange apparatus 100 is shown, according to an exemplary aspect. Figure 4A is a schematic top perspective view of a reticle exchange apparatus 100 according to an exemplary aspect. Figure 4B yes Figure 4A FIG. 1 is a schematic partial cross-sectional view of a reticle exchange apparatus 100 shown in FIG.

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

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

[0077] like Figure 4A and Figure 4B As shown in FIG, the reticle base plate 406 can hold the reticle 300 so that the reticle base plate front side 407 and the reticle back side 304 each face the bottom platform surface 202 and the fixture front side 252. For example, the reticle base plate front side 407 and the reticle back side 304 can be vertically facing away from the bottom platform surface 202 and the fixture front side 252. Figure 4B As shown in FIG, the reticle exchange apparatus 100 may include a reticle exchange area 410, which is a cross-sectional area of the clamp 250, the reticle 300, the reticle base plate 406, and the reticle conveyor arm 404 during the reticle exchange process.

[0078] In one example, during a reticle exchange process, reticle transport arm 404 of reticle transport device 402 positions reticle 300 on reticle base plate 406 toward gripper 250 in reticle exchange area 410. As described above, the transfer of the reticle from reticle transport device 402 to gripper 250 and from gripper to reticle transport device can relieve thermal stress in reticle 300 and reduce parasitic thermal effects in 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) for transferring a pattern to a substrate (e.g., substrate W). Reticle heating and / or cooling can cause changes in reticle properties, which can affect the radiation beam path (e.g., focus) and cause deformation of the patterned substrate (e.g., overlay error). Changes in reticle properties can be modeled and corrected by a reticle heating model. Current reticle heating models rely on a sensor-based, application-specific approach to calibrate the reticle heating model using RTS and require calibration across batches of production wafers.

[0081] In some cases, this approach can be inaccurate and inefficient because the RTS can exhibit errors, potentially introducing unnecessary delays and requiring rework of production wafers. In some aspects, the RTS has a temperature gradient variation of approximately ±0.6°C, which can result in an overlay mismatch of approximately 1 nm / °C. Furthermore, in some aspects, each reticle temperature measurement performed by the RTS takes approximately five seconds per wafer, which can introduce additional delays. Furthermore, in some aspects, pre-conditioning the reticle in the internal reticle library (IRL) can take additional time to condition (e.g., cool) the reticle to the desired temperature (e.g., 22°C ± 0.2°C), and some reticles may remain in the IRL longer than necessary. For example, due to pre-conditioning delays, delays of up to seven minutes can occur, which can translate into lost production of up to thirty-five production wafers per occurrence. Furthermore, changes in the reticle's thermomechanical properties prior to calibration can amplify and exacerbate overlay mismatch (e.g., increasing it from 1 nm / °C to over 2.1 nm / °C). Additionally, production wafers for calibration may be reworked over time, which may introduce additional delays and reduce overall throughput.

[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 stress in the reticle, avoid rework of production substrates, and / or increase the manufacturing throughput and yield of the lithography process.

[0083] Figures 5 to 8 Reticle calibration methods 500 , 600 are illustrated 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 According to exemplary aspects, Figure 6 Schematic diagram of k4 parameter 700 of reticle calibration method 600 shown in FIG. Figure 8 According to exemplary aspects, Figure 6 Schematic diagram of k18 parameter 800 of reticle calibration method 600 shown in FIG.

[0084] Figure 5 A reticle calibration method 500 is illustrated 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 a photolithography process. The reticle calibration method 500 can also be configured to increase the accuracy and speed of calibration of the reticle heating model and increase the manufacturing throughput and yield of the photolithography process. Although the reticle calibration method 500 is Figure 5Although shown as stand-alone methods and / or systems, aspects of the present disclosure may be used with other apparatus, systems and / or methods, such as, but not limited to, lithography apparatus LA, lithography cell LC, computer system CL, metrology tool MT, support structure MT, pattern forming device MA, mask exchange apparatus 100, mask platform 200, mask 300, IVR 400 and / or mask calibration method 600.

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

[0086] In some aspects, reticle 300 can be conditioned (e.g., heated and / or cooled) by an IRL. For example, reticle 300 can be placed in an IRL for approximately forty minutes to reach a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, reticle 300 can be conditioned (e.g., heated and / or cooled) by a conditioning bath that rapidly heats and / or cools reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C). For example, the conditioning bath can include a resistive heater and / or a nozzle to flow a gas (e.g., air, nitrogen, argon, helium, etc.) throughout reticle 300 to rapidly heat and / or cool 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.

[0087] In some aspects, the conditioning phase 510 can include RA measurements and / or RSD measurements 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 can be measured to determine the conditioned reticle temperature 512. In some aspects, the RSD measurements can be converted by the FEM into the conditioned reticle temperature 512. In some aspects, the conditioning phase 510 can include RA measurements between the reticle 300 and a non-production substrate. For example, the non-production substrate can include one or more CTC wafers used for alignment and / or reticle temperature calibration.

[0088] In some aspects, the conditioning phase 510 can include conditioning the reticle 300 in the reticle stage 200 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 greater than 22°C ± 0.2°C), a maximum of about forty or fewer production substrates (e.g., about twenty-two to about twenty-six wafers) may be required to condition the production batch, whereas if the reticle 300 is close to a "perfectly conditioned" state (e.g., 22°C ± 0.2°C), a minimum of about two or more production substrates (e.g., about two to about six wafers) may be required to condition the production batch.

[0089] In some aspects, the adjustment stage 510 can include adjusting 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, the decision-based and / or machine learning can 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 adjustment phase 510 can include adjusting the reticle 300 in the reticle platform 200 by using a KPI 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, Figure 7 and Figure 8 As shown in , k4 parameter 700 and / or k18 parameter 800 can be measured, and convergence (eg, convergence ≥ 90%) of average k4 parameter 710 and / or average k18 parameter 810 can be used to determine the temperature of reticle 300 and / or calibration of the reticle heating model.

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

[0092] In some aspects, an initial estimate of parameters for the reticle heating model can be based on 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 the 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 calibration of the reticle heating model is completed using the one or more non-production substrates, production of production substrates in the batch is initiated, and calibration based on RA measurements continues throughout processing stage 530.

[0093] In some aspects, the calibration phase 520 can include RA measurements and / or RSD measurements to determine the temperature of the reticle 300. In some aspects, the calibration phase 520 can include an online, 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 particular phase (e.g., the adjustment phase 510) can be compared between two different non-production substrates and / or non-production batches, and the difference (e.g., the differential reticle temperature) can be adjusted in the reticle heating model. ) or trends (e.g. =0.5°C).

[0094] In some aspects, the calibration phase 520 can include evaluating the reticle heating model for each RA measurement between the reticle and a plurality of non-production substrates in a non-production batch. For example, the evaluation can include updating a parameter x of the lithography process (e.g., radiation dose, focus, alignment, etc.) 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, calibration phase 520 can also be configured to condition (e.g., heat) the reticle 300 to a dose temperature 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 calibration phase 520 is a predetermined temperature (e.g., 22°C ± 0.2°C) in a "perfectly regulated" state. In one aspect, calibration phase 520 heats the reticle 300 to the dose temperature (e.g., approximately 24°C), as shown in calibration reticle temperature 522. In some aspects, calibration phase 520 can include RA measurements and / or RSD measurements to determine the temperature of the reticle 300. In some aspects, the non-production substrate can include one or more CTC wafers used for dose calibration.

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

[0099] In some aspects, processing stage 530 can 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 calibration of the reticle heating model is completed using one or more non-production substrates (e.g., during calibration stage 520), production of the production substrates in the batch begins, and calibration based on RA measurements continues throughout processing stage 530.

[0100] In some aspects, processing stage 530 can include RA measurements and / or RSD measurements to determine the temperature of reticle 300. In some aspects, processing stage 530 can include an online, 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., adjustment stage 510) can be compared between two different production substrates and / or production batches, and the difference (e.g., differential reticle temperature) can be adjusted in the reticle heating model. ) or trends (e.g. =0.5°C).

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

[0102]

[0103] 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.

[0104] In some aspects, the reticle calibration method 500 can 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 measurement can be performed in each stage, and the RSD measurement can be performed only once in each stage. In some aspects, the decision-based and / or machine learning methods used in the conditioning stage 510 to determine the temperature of the reticle 300 can also be used in the calibration stage 520 and / or the processing stage 530.

[0105] In some aspects, the reticle calibration method 500 can be implemented by a computer system CL, which can function as a controller and / or processor to control the various stages and measurements of the reticle calibration method 500. In some aspects, the reticle calibration method 500 can be implemented by a lithographic apparatus LA, which can include a controller and / or processor to control the various stages and measurements of the reticle calibration method 500. In some aspects, the reticle calibration method 500 can be implemented by a program on a non-transitory computer-readable medium, for example, on a computer system CL, which can function as a controller and / or 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 in FIG. 5 are similar to, for example, Figure 6 Aspects of the reticle calibration method 600 shown in FIG. 6 may be similar. Similar reference numerals are used to indicate Figure 5 Features of aspects of the reticle calibration method 500 shown in Figure 6 Similar features to aspects of the reticle calibration method 600 shown in FIG.

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

[0108] like Figure 6 As shown in FIG, a reticle calibration method 600 may include a reticle temperature 602, a process flow 604, a conditioning phase 610, a stress reduction phase 620, a calibration phase 630, and / or a treatment phase 640. The conditioning phase 610 may be configured to adjust the 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 originates in the lithography system (e.g., an IRL, an external metrology tool MT, a reticle stage 200, an IRIS, etc.). For example, the reticle 300 may initially be in a "hot" state (e.g., a reticle temperature greater than 22°C ± 0.2°C), a "cold" state (e.g., a reticle temperature less than 22°C ± 0.2°C), and a "perfectly conditioned" state (e.g., a reticle temperature of 22°C ± 0.2°C). In one aspect, the conditioning phase 610 may include adjusting RA and RSD measurements 611 to determine an initial temperature of the reticle 300. In one aspect, the conditioning phase 610 cools and / or heats the reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C), such as Figure 6 This is shown by adjusting the reticle temperature 612.

[0109] In some aspects, reticle 300 can be conditioned (e.g., heated and / or cooled) by an IRL. For example, reticle 300 can be placed in an IRL for approximately forty minutes to reach a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, reticle 300 can be conditioned (e.g., heated and / or cooled) by a conditioning bath that rapidly heats and / or cools reticle 300 to a predetermined temperature (e.g., 22°C ± 0.2°C). For example, the conditioning bath can include a resistive heater and / or a nozzle to flow a gas (e.g., air, nitrogen, argon, helium, etc.) throughout reticle 300 to rapidly heat and / or cool 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 (eg, 22°C ± 0.2°C). Figure 6 As shown in FIG, an adjustment RA and RSD measurement 611 may be performed to determine the initial temperature of the mask 300 in the adjustment phase 610. For example, one or more alignment marks 310 (shown in FIG) on the mask 300 may be measured. Figure 3A and Figure 3B ) and one or more edge alignment marks 320 (shown in Figure 3A and Figure 3B In some aspects, the RSD measurement can be converted by the FEM to adjust the reticle temperature 612. In some aspects, the adjustment phase 610 can include one or more RA measurements between the reticle 300 and a non-production substrate. For example, Figure 6 As shown in FIG, the conditioning phase 610 may include a conditioning RA and RSD measurement 611, a second conditioning RA measurement 614 (if required), a third conditioning RA measurement 616 (if required), and / or a fourth conditioning RA measurement 618 (if required) 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 may include one or more CTC wafers used for alignment and / or reticle temperature calibration.

[0111] In some aspects, the conditioning phase 610 can include conditioning the reticle 300 in the reticle stage 200 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 greater than 22°C ± 0.2°C), a maximum of about forty or fewer production substrates (e.g., about twenty-two to about twenty-six wafers) may be required to condition the production batch, whereas if the reticle 300 is close to a "perfectly conditioned" state (e.g., 22°C ± 0.2°C), a minimum of about two or more production substrates (e.g., about two to about six wafers) may be required to condition the production batch.

[0112] In some aspects, the adjustment phase 610 may include adjusting the reticle 300 in the reticle platform 200 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, the 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 filter) are aligned with the timing specifications of the lithography process (e.g., process window) with similarly high accuracy. In some aspects, the adaptive window can be used to determine whether there is any degradation and / or drift of the KPIs (e.g., k4 parameter, k18 parameter). For example, four RA measurements (e.g., the past three measurements and the current measurement) may be taken and a check performed to verify whether any changes have occurred between the RA measurements. If a change is detected, the adjustment phase 610 continues, and if no change is detected, the adjustment phase 610 is completed (eg, stopped). In some aspects, the minimum time for the adjustment phase 610 is about one minute, and the maximum time for the adjustment phase 610 is about five minutes.

[0113] In some aspects, the adjustment phase 610 can include adjusting the reticle 300 in the reticle platform 200 by using a KPI 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, Figure 7 and Figure 8 As shown in , k4 parameter 700 and / or k18 parameter 800 can be measured, and the convergence (e.g., convergence ≥ 90%) of average k4 parameter 710 and / or average k18 parameter 810 can be used to determine the temperature of reticle 300 and / or calibration parameters of the reticle heating model. Figure 6As shown in , the adjustment phase 610 may include an adjustment RA and RSD measurement 611, a second adjustment RA measurement 614, a third adjustment RA measurement 616, and / or a fourth adjustment RA measurement 618 to measure KPIs (e.g., k4 parameter 700, 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 stage 620 can be configured to reduce parasitic thermal effects in the reticle 300. In one aspect, as Figure 6 As shown in FIG6 , stress reduction phase 620 may include a removal step 621 and a zero-dose step 622. Removal step 621 may be configured to release stress from reticle 300 and thereby reduce parasitic thermal effects by removing reticle 300 from reticle stage 200 to IVR 400. Zero-dose step 622 may be configured to release stress from reticle 300 and thereby reduce parasitic thermal effects by exposing reticle 300 and a non-production substrate to zero-dose radiation. In one aspect, the initial temperature of reticle 300 at the start of stress reduction phase 620 is a predetermined temperature (e.g., 22°C ± 0.2°C) in a "perfectly regulated" state. In one aspect, stress reduction phase 620 reduces parasitic thermal effects in reticle 300 by releasing stress in removal step 621 and then exposing reticle 300 in zero-dose step 622 to further reduce parasitic thermal effects, as shown in stress-reduced reticle temperature 624. In one aspect, stress reduction phase 620 maintains reticle 300 at a predetermined temperature (eg, 22° C. ± 0.2° C.) in a “perfectly conditioned” state. In one aspect, zero dose step 622 can include zero dose RA and RSD measurements 623 to verify the temperature of reticle 300 .

[0115] In some aspects, stress in reticle 300 can be reduced by removing reticle 300 from reticle stage 200 and quickly returning reticle 300 to reticle stage 200. For example, Figure 4A and Figure 4B As shown in , reticle 300 can be released from reticle holder 224 and clamp 250 on reticle stage 200 and transferred to reticle base plate 406 of IVR 400, and then immediately transferred back to reticle stage 200 and clamped by reticle holder 224 and clamp 250. In some aspects, stress in reticle 300 can be reduced by exposing reticle 300 and a non-production substrate (e.g., a CTC wafer) to zero dose radiation. For example, Figure 6As shown in , after the removal step 621, a zero dose step 622 can begin 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, Figure 6 As 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 used for zero dose calibration.

[0116] Calibration phase 630 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 calibration phase 630 is a predetermined temperature (e.g., 22°C ± 0.2°C) in a "perfectly regulated" state. In one aspect, calibration phase 630 can include calibration RA and RSD measurements 631 to verify the temperature of the reticle 300. In one aspect, calibration phase 630 heats the reticle 300 to a dose temperature (e.g., above 22°C ± 0.2°C), as shown in calibration reticle temperature 632. In one aspect, during calibration phase 630, a non-production substrate is exposed to a dose of radiation to allow for in-process calibration of the reticle heating model in the production environment itself. In one aspect, an initial estimate of the parameter requiring calibration (e.g., x) is made based on the reticle heating model (e.g., FEM) and the reticle temperature (e.g., calibration reticle temperature 632).

[0117] In some aspects, an initial estimate of parameters for the reticle heating model can be based on 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 the 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 calibration of the reticle heating model is completed using the one or more non-production substrates, production of production substrates in the batch is initiated, and calibration based on RA measurements continues throughout processing stage 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, Figure 6As shown in FIG, calibration RA and RSD measurements 631 can be performed to verify the initial temperature of the reticle 300 at the beginning of the calibration phase 630. In some aspects, the calibration phase 630 can include an online, real-time calibration based on a reticle heating model for one or more non-production substrates and / or one or more non-production batches. For example, the reticle temperature in a particular phase (e.g., adjustment phase 610) can be compared between two different non-production substrates and / or non-production batches, and the difference (e.g., differential reticle temperature) can be adjusted in the reticle heating model. ) or trends (e.g. =0.5°C).

[0119] In some aspects, the calibration phase 630 can include evaluating the reticle heating model for each RA measurement between the reticle 300 and a plurality of non-production substrates in a non-production batch. For example, the evaluation can include updating a 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 a plurality of 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) the reticle 300 to a 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 beginning of the calibration phase 630 is a predetermined temperature (e.g., 22°C ± 0.2°C) in a "perfectly conditioned" state. In one aspect, the calibration phase 630 heats the reticle 300 to the dose temperature (e.g., approximately 24°C), as shown in calibration 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, Figure 6 As 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 used for dose calibration.

[0123] Processing stage 640 can be configured to process (e.g., manufacture) 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 processing stage 640 is the dose temperature (e.g., approximately 24°C). In one aspect, processing stage 640 can include processing RA and RSD measurements 641 to verify the temperature of the reticle 300. In one aspect, processing stage 640 further heats the reticle 300 to a dose production temperature (e.g., ≥ 24°C) in a "hot" state, as shown by processing reticle temperature 642. In one aspect, during processing stage 640, the production substrate is exposed to a dose of radiation to allow for in-process calibration of the reticle heating model within the production environment itself. In one aspect, an initial estimate of a parameter requiring calibration (e.g., x) 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, process stage 640 can 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 calibration of the reticle heating model is completed using one or more non-production substrates (e.g., during calibration stage 630), production of the production substrates in the batch begins, and calibration based on RA measurements continues throughout process stage 640.

[0125] In some aspects, processing stage 640 may include RA measurements and / or RSD measurements to determine the temperature of reticle 300. For example, Figure 6 As shown in FIG, process RA and RSD measurements 641 can be performed to verify the initial temperature of the reticle 300 at the beginning of process phase 640. In some aspects, process phase 640 can include an online, 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 phase (e.g., adjustment phase 610) can be compared between two different production substrates and / or production batches, and the difference (e.g., differential reticle temperature) can be adjusted in the reticle heating model. ) or trends (e.g. =0.5°C).

[0126] In some aspects, processing stage 640 can include evaluating the reticle heating model for each RA measurement between the reticle 300 and a plurality of production substrates in a production batch. For example, the evaluation can include updating a parameter x of the lithography process (e.g., radiation dose, focus, alignment, etc.) 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., during the conditioning stage 610, the stress reduction stage 620, the calibration stage 630, and the processing stage 640). For example, the RA measurement can be performed during each stage, and the RSD measurement can be performed only once during each stage. In some aspects, the decision-based and / or machine learning methods used to determine the temperature of the reticle 300 during the conditioning stage 610 can also be used during 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 dynamics. 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., reticle heating model parameters) based on various internal (e.g., resist) data. In some aspects, the reticle calibration method 600 can include sinusoidal sweep exposures for both reticle heating model calibration and lens calibration. For example, by using sinusoidal sweep exposures (e.g., with a fixed period), different time constants (e.g., via RA and / or RSD measurements) can be extracted for the reticle heating model parameters and lens parameters used for calibration.

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

[0132] Figure 7The K4 parameter 700 is shown in accordance with an exemplary aspect. The K4 parameter 700 can be configured to increase the accuracy and speed of calibration of the mask heating model. The K4 parameter 700 can also be configured to determine the temperature of the mask 300. The K4 parameter 700 represents the Y-axis magnification deformation. Although the K4 parameter 700 is Figure 7 Although shown as stand-alone methods and / or systems, aspects of the present disclosure may be used with other apparatus, systems and / or methods, such as, but not limited to, lithography apparatus LA, lithography cell LC, computer system CL, metrology tool MT, mask calibration method 500 and / or mask calibration method 600.

[0133] like Figure 7 As shown in FIG, k4 parameter 700 may include intensity (arbitrary units) 702, number of wafers 704, and average k4 parameter 710. In some aspects, k4 parameter 700 may be measured based on deformation measured by RA and / or RSD to determine the temperature of reticle 300. For example, Figure 7 As shown in , an average k4 parameter 710 can be measured over a number of wafers, and the convergence (e.g., ≥ 90%) of the average k4 parameter 710 can be used to determine the temperature of the reticle 300 and / or 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 The k18 parameter 800 is shown in accordance with an exemplary aspect. The k18 parameter 800 can be configured to increase the accuracy and speed of calibration of the mask heating model. The k18 parameter 800 represents the Y-axis barrel deformation. Although the k18 parameter 800 is Figure 8 Although shown as stand-alone methods and / or systems, aspects of the present disclosure may be used with other apparatus, systems and / or methods, such as, but not limited to, lithography apparatus LA, lithography cell LC, computer system CL, metrology tool MT, mask calibration method 500 and / or mask calibration method 600.

[0135] like Figure 8 As shown in FIG, k18 parameter 800 may include intensity (arbitrary units) 802, number of wafers 804, and average k18 parameter 810. In some aspects, k18 parameter 800 may be measured based on deformation measured by RA and / or RSD to determine the temperature of reticle 300. For example, Figure 8As shown in , an average k18 parameter 810 can be measured over 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 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] Example Reticle Calibration Chart

[0137] Figure 9 and Figure 10 Reticle calibration maps 900 , 1000 are illustrated for reducing the effects of heating and / or cooling the reticle 300 during a photolithography process according to exemplary aspects. Figure 9 A reticle calibration chart 900 is shown according to an exemplary aspect. It should be understood that it is not necessary to Figure 9 In addition, the disclosure provided herein can be performed simultaneously, continuously and / or in a manner similar to Figure 9 The reticle calibration chart 900 should be referenced to Figure 3A 、 Figure 3B 、 Figure 4A 、 Figure 4B 、 Figure 5 and Figure 6 However, reticle calibration chart 900 is not limited to those example aspects.

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

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

[0140] In step 906, if Figure 3A 、 Figure 3B 、 Figure 5 and Figure 6 As shown in the example of , the reticle heating model is calibrated by exposing 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 a 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 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 batches. In some aspects, the reticle heating model can be evaluated for each RA measurement between reticle 300 and multiple non-production substrates in a non-production batch.

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

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

[0143] Figure 10A reticle calibration chart 1000 is shown according to an exemplary aspect. It should be understood that it is not necessary to Figure 10 In addition, the disclosure provided herein can be performed simultaneously, continuously and / or in a manner similar to Figure 10 The reticle calibration chart 1000 should be referenced to Figure 3A 、 Figure 3B 、 Figure 4A 、 Figure 4B 、 Figure 5 and Figure 6 However, reticle calibration chart 1000 is not limited to those example aspects.

[0144] In step 1002, if Figure 3A 、 Figure 3B 、 Figure 5 and Figure 6 As shown in the example of FIG, reticle 300 is heated and / or cooled to a temperature (e.g., 22°C ± 0.2°C) based on an RSD measurement. In some aspects, the RSD measurement can be converted to a reticle temperature by the FEM. In some aspects, reticle 300 can be heated and / or cooled by rapidly heating and / or cooling a conditioning bath of reticle 300. In some aspects, one or more RA measurements and RSD measurements can be taken to determine when reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C). In some aspects, decision-making and / or machine learning can be used to determine when reticle 300 has reached a predetermined temperature (e.g., 22°C ± 0.2°C).

[0145] In step 1004, if Figure 3A 、 Figure 3B 、 Figure 4A 、 Figure 4B and Figure 6 As shown in the example of FIG, reticle 300 is removed from reticle stage 200 and then returned to reticle stage 200 to release thermal stress. In some aspects, stress (e.g., induced stress, internal strain) in reticle 300 can be released by removing reticle 300 from reticle stage 200 to IVR 400 and quickly returning reticle 300 from IVR 400 to reticle stage 200, thereby reducing parasitic thermal effects.

[0146] In step 1006, if Figure 3A 、 Figure 3B and Figure 6As shown in the example of FIG, , the reticle 300 and the non-production substrate are exposed to zero dose of radiation to reduce parasitic heating effects. In some aspects, 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., a CTC wafer) to zero dose of radiation, thereby reducing parasitic heating effects.

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

[0148] In step 1010, if Figure 3A 、 Figure 3B 、 Figure 5 and Figure 6 As shown in the example of FIG, , a reticle 300 and a non-production substrate are exposed 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 used for dose calibration.

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

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

[0151] The above techniques allow for the determination of Reticle Heating Calibration (RHC) data. RHC data provides information about how a reticle heats up from a cold state. RHC data can be used to improve the accuracy of estimates of reticle deformation that rely on RA measurements.

[0152] Figure 5 and Figure 6 A conditioning phase, a calibration phase, and a processing phase are shown. In each of these phases, the temperature of the reticle is varied within a temperature range. RA measurements can be performed using the reticle at different temperatures within each temperature range. As described above, a model such as an FEM model can be used to determine the stresses generated and the resulting deformation of the reticle. RHC data can be generated based on the RA measurements at different temperatures and the corresponding stresses and deformations at each temperature. The RHC data thus allows determination of how the reticle is heated from a cold state and the resulting stresses and deformations. The deformation can be determined as a deformation pattern, such as the k parameter described earlier.

[0153] According to a first embodiment, RHC data is used to improve the accuracy of a reticle heating model. The reticle heating model may include the RHEA described earlier. RHEA is a modal deformation method in which the modeled deformation relies on RA measurements.

[0154] Figure 11 The deterministic reticle heating model is shown. The model includes RHEA 1101, reticle heating module 1102 and uncertainty module 1103.

[0155] Inputs to the RHEA can include a nominal reference state 1104 and RA feedback data 1105. The nominal reference state 1104 is data describing the initial state of the reticle. The nominal reference state 1104 can be retrieved from a library. The RA feedback data 1105 can include operational data, such as the applied dose. The RHEA output 1106 can include the heating dynamics determined by the RHEA 1101. The RHEA output 1106 can be provided to the reticle heating module 1102.

[0156] Uncertainty module 1103 represents the contribution to the actual deformation of the reticle that the deterministic reticle heating module cannot predict. Specifically, the uncertainty may include events such as timing changes or changes that result in different boundary conditions.

[0157] The reticle heating module 1102 can determine and output the determined mode shape as the reticle deformation.A process correction for changing the operation of the lithographic apparatus can be determined in dependence on the output of the reticle heating model to at least partially compensate for the reticle deformation.

[0158] about Figure 11 A problem with the reticle heating model in

[11] is that the accuracy of the model is dependent on a reference state 1104 that describes the initial state of the reticle. Reference state 1104 assumes that the reticle is perfectly adjusted. Therefore, if the reticle is not perfectly adjusted, the accuracy of the reticle heating model can be substantially reduced.

[0159] The actual temperature reached by the reticle depends on the reticle's history and can vary between approximately 20°C and 24°C. For example, if the reticle is delivered from outside the lithographic apparatus, the reticle temperature will depend on the temperature within the fabrication facility. If the reticle is provided by a reticle stage, the reticle temperature will depend on the number of exposures performed using the reticle, as well as the dose of the exposures. If the reticle is provided from a thermal conditioning tank, the reticle temperature will depend on the type of thermal conditioning tank and the length of time the reticle has been in the conditioning tank.

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

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

[0162] Figure 12 A new deterministic reticle heating model according to the present embodiment is shown. The model according to the present embodiment is improved by applying a calibration to the nominal reference state 1104 Figure 11 The applied calibration improves the accuracy of the model by at least partially reducing the effect of the variable initial temperature of the reticle.

[0163] The model includes RHEA 1203 , reticle reference module (RRM) 1202 and reference masker (RM) module 1201 .

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

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

[0166] RRM input 1206 may also include reticle transport data received from reticle transport device 402. The reticle transport data may include data regarding how the reticle was transported. The reticle transport data may include location data describing the locations where the reticle was located. The reticle transport data may include time data describing how long the reticle was at each location. The reticle transport data may include thermal data describing the temperature at each location where the reticle was located. The reticle transport data may include data regarding the thermal properties of the reticle at each location.

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

[0168] The RRM 1202 may receive updated input for each batch of substrates being processed and / or whenever an event occurs with the reticle transport apparatus 402 .

[0169] RRM output 1210 may be data received by RRM 1202, or data generated dependent on data received by RRM 1202. RRM output 1210 may be input to RM 1201. RRM 1202 may provide RRM output 1210 when a first RA measurement with the reticle is performed for each use of the reticle.

[0170] RM input 1204 may also include RA measurement data and exposure data.RM input 1204 may be provided to RM 1201 when a first RA measurement with the reticle is taken for each use of the reticle.

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

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

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

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

[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 of substrates being processed and / or whenever an event occurs with the reticle transport apparatus 402. The RA feedback data 1209 may be compared to an earlier reference Figure 11 The RA feedback data described is the same.

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

[0177] RHEA output 1207 may include heating dynamics that may be input to reticle heating module 1102 for determining and outputting mode shapes, which are determinations of the deformation of the reticle, as described earlier with reference to FIG. Figure 11 Alternatively, the reticle heating module 1102 may not be present, and the RHEA output 1207 may include a determination of the mode shape as a determination of the deformation of the reticle.

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

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

[0180] At the beginning of processing 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 measurements may be performed. RA measurements may be input to RM 1201. RM 1201 may use the data received by RRM 1202 to determine reference shape data for the reticle. RM 1201 may estimate 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 determined by Shown to remove any pre-existing systematic effects on the reticle heating calibration KPIs (eg, r4, r18, r10, etc.).

[0184] The calibration process can separate the stress effects from the thermomechanical effects of the mask heating behavior. This allows the stress-induced effects to be distinguished and reduced. Figure 6 As described, the reticle can be cooled during a conditioning phase, during which stress is present in the reticle. A stress reduction phase can then be performed to substantially reduce the stress. The substantially unstressed reticle can then be heated during a calibration phase and a treatment phase across a temperature range that substantially overlaps the temperature range within which the reticle was cooled during the conditioning phase. The stress effects can be determined based on a comparison of the stressed state of the reticle with the substantially unstressed state. Specifically, a filtering operation can be performed. to remove any systemic effects. Indicates the adjustment phase and In the case of a calibration phase and / or a processing phase, the comparison of the stressed state of the reticle with the substantially unstressed state can determine ,as follows:

[0185]

[0186] Can be used to determine a 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 changes in the introduced temperature of the reticle.

[0189] Figure 13The difference in the modeled ratio of overlap to reticle temperature when processing a batch of substrates W for both the known model 1302 and the new model 1301 according to the present embodiment is shown.

[0190] exist Figure 13 In Figure 1, the y-axis represents the modeled ratio of overlap to reticle temperature. The x-axis represents the time it takes to process a batch of substrates. Known model 1302 does not use a calibrated reference state for the reticle and incorrectly assumes the reticle is perfectly adjusted. Model 1301 according to this embodiment improves upon the known model by using a calibrated reference to determine calibrated reference state 1205. 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. As a result, process corrections applied in response to the modeled reticle deformation are more appropriate, thereby improving overlay performance without reducing system productivity. The model's performance can be less sensitive to changes in reticle temperature. Therefore, the accuracy of the model is improved when using a reticle that is not in a perfectly adjusted state. Overlay effects caused by using a hot reticle can be reduced by approximately half, and the system's sensitivity to changes in applied process corrections is reduced. This embodiment eliminates the need for a temperature sensor to measure the reticle's temperature.

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

[0193] A photolithography 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 reusing the first reticle on the batch of substrates. This may occur, for example, when a first pattern is desired on a first layer of a substrate, a second pattern is desired on a second layer of the substrate, and the same first pattern is desired again on a third layer of the substrate.

[0194] Prior to the first use of a first reticle, the first reticle may initially be in a cold state and properly conditioned in an IRL for use. The first reticle may then be heated while being used in a first photolithography process performed on the batch of substrates. The first reticle is then not used while performing a photolithography process using a second reticle, and thus, the first reticle cools during this period. The first reticle is then reused. 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 a cold state.

[0195] Figure 14This diagram schematically illustrates the overlay error that can be caused by the temperature of the reticle without performing a process to correct this source of overlay error. During time period A1, the reticle is used and heated. During time period B, the reticle is not used and allowed to cool. During time period A2, the reticle is used again. Figure 14 The illustration shows that when time period B is short, the reticle cannot cool to the same cold state as at the beginning of time period A1. If the reticle heating model assumes that the reticle is in a cold state at the beginning of time period A2, the modeled deformation of the reticle will be inaccurate. Consequently, the process correction determined to compensate 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 fast batch changeover occurs, which can be used to improve the accuracy of the reticle heating model.

[0197] According to this embodiment, reticle transport is tracked and used to generate reticle transport data. The reticle transport data includes data about each location the reticle has been in, as well as the time the reticle was in each location. A determination is made based on the reticle transport data and the known thermal properties of the reticle to determine whether a rapid batch changeover has occurred. Decisions about how to configure the reticle heating model can then be made based on whether a rapid batch changeover has occurred.

[0198] When a 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 properly improved by IRL. Initialization of the reticle heating model may include setting reference data based on the first reticle alignment measurement of substrates in the batch. The reference data may include, for example, the nominal reference state 1104 described for the first embodiment. All states of the model may be initialized to zero or other default values for when the reticle is in its cold state.

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

[0200] After the first batch of substrates has been processed, a batch changeover process may occur. All states of the reticle heating model at the end of processing of the first batch of substrates are saved. A photolithography process may then be performed using a different reticle, or no photolithography process may be performed.

[0201] For each reticle that can be used in a performed lithography process, reticle transport data can be generated. The reticle transport data may include data about how the reticle was transported. The reticle transport data may include location data describing the location where the reticle was located. The reticle transport data may include time data describing how long the reticle was at each location. The time data may also include data about the time of each start and end of a lithography process performed using the reticle and the time of the start and end of any other related processes. The reticle transport data may include thermal data describing the temperature at each location where the reticle was located. The reticle transport data may include data about the thermal properties of the reticle at each location. The reticle transport data in this embodiment may be the same as the reticle transport data generated and used in the first embodiment.

[0202] According to this embodiment, at the beginning of the process of reusing each reticle, a determination regarding reticle conditioning is made based on the reticle transport data. Specifically, an estimate of the reticle temperature can be made based on the reticle transport data. If the estimated temperature is at or above a threshold, a determination is made that the reticle is in a hot state. This determination that the reticle is in a hot state can be equivalent to a determination that a rapid batch changeover has occurred. If the estimated temperature is below the threshold, a determination is made that the reticle is in a cold state. This determination that the reticle is in a cold state can be equivalent to a determination that a rapid batch changeover has not yet occurred.

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

[0204] If it is instead determined that the reticle is in a hot state, the reticle heating model for the process of reusing the reticle is instead initialized using a previously saved state of the reticle heating model at the end of processing a previous batch of substrates using the reticle, thereby more appropriately initializing the model given the state of the reticle.

[0205] Advantageously, the reticle transport data allows for detection of rapid batch changes (such as in an ABA scenario) and provides for more appropriate initialization of the reticle heating model when the loaded reticle at the start of the process is warm rather than cold. The techniques of this embodiment can substantially reduce errors caused by the sensitivity of the reticle heating model to rapid batch changes. The techniques of this embodiment can be applied computationally without reducing the throughput of the lithographic apparatus.

[0206] This embodiment can be used with any mask heating model. This embodiment can be used in combination with the first embodiment. Specifically, the determination of the state of the mask can be performed by the RRM 1202 that receives the mask feed data. Therefore, 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 timing anomaly can be generally defined as any timing anomaly that may occur while performing a lithography process. Examples of track timing anomalies include any event that causes an unexpected delay in substrate loading time, a computational glitch that delays an instructed operation, and any of many other unplanned events that may occur.

[0209] The same reticle is used while performing a lithography process on multiple substrates in a batch. Track timing anomalies can occur during processing of the batch. Known reticle heating models do not account for track timing anomalies. The occurrence of track timing anomalies is therefore a source of inaccuracy in reticle heating models, so the impact of timing anomalies on the actual thermal state of the reticle is not modeled.

[0210] This embodiment provides a technique for both detecting when a track timing anomaly occurs and determining whether it is appropriate to reinitialize the reticle heating model in response to the track timing anomaly. This technique can be used to improve the accuracy of the reticle heating model.

[0211] According to this embodiment, while a reticle is loaded onto a reticle stage and remains clamped to the reticle stage, the processes utilizing the reticle are tracked and used to generate reticle process data. The reticle process data includes timing data regarding exposure processes performed using the reticle, as well as any other processes utilizing the reticle while it is clamped to the stage. A reticle heating model can be configured based on the reticle process data. Specifically, the occurrence and impact of track timing anomalies can be determined based on the reticle process data and the known thermal properties of the reticle. The reticle heating model can then be configured based on whether the track timing anomaly has a substantial impact on the thermal properties of the reticle.

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

[0213] When a 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 properly improved by IRL. 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 with respect to the first embodiment. All states of the reticle heating model can be initialized to zero or other default values for the reticle when it is in a cold state.

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

[0215] Reticle process data is generated, including timing data regarding exposure processes performed using the reticle, data regarding the dose of each exposure process, and data regarding any other processes that affect the properties of the reticle while the reticle remains clamped to the reticle stage. The reticle process data can be monitored and used to determine when a track timing anomaly occurs. For example, a track timing anomaly can be determined to have occurred when an exposure process has not been performed within an expected time window for the exposure process. The determination that a track timing anomaly has occurred can also be made based on other parts of the overall lithography system. For example, the determination that a track timing anomaly has occurred can be made based on the operation of the substrate transport device.

[0216] When a determination is made that a track timing anomaly has occurred, the impact of the track timing anomaly on the reticle is determined. The duration of the track 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 track timing anomaly is long enough to cause a substantial change in the temperature of the reticle. Specifically, the temperature change of the reticle can be estimated. When the temperature change is at or above a threshold, a long track timing anomaly can be determined to have occurred. When the temperature change is below a threshold, a short track timing anomaly can be determined to have occurred.

[0217] Use of the reticle held clamped to the stage is quickly resumed after the track timing anomaly ends.A reticle heating model for the reticle is then configured depending on whether the track timing anomaly is a short track timing anomaly or a long track timing anomaly.

[0218] When a determination is made that the track timing anomaly is a short track timing anomaly, the reticle heating model is configured based on the state of the heating model before the track timing anomaly occurred. In other words, the reticle heating model may not be substantially reconfigured, and the reticle heating model may operate as if the track timing anomaly had not occurred.

[0219] When a determination is made that the track timing anomaly is a long track timing anomaly, the reticle heating model can be configured as if the reticle is in a cold state. In other words, the reticle heating model can be reconfigured to the same states that were used to initialize the reticle heating model when the reticle was 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 when it is in its cold state.

[0220] Advantageously, this embodiment provides a more appropriate configuration of the reticle heating model when a 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 track timing anomalies. The techniques of this embodiment can be computationally applied without reducing the throughput of the lithographic apparatus.

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

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

[0223] As described earlier, the reticle is clamped to reticle stage 200. A potential problem is that the clamping force holding the reticle may vary over time. This may be caused, for example, by frictional stresses caused by the locking between the reticle and reticle stage 200. Substantial changes in clamping force can occur over a period of approximately 4 to 8 hours and, if not compensated for, can increase overlay error by approximately 2 nm.

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

[0225] Figure 15Reticle 1501 is shown. Reticle 1501 is surrounded by horizontally aligned edge marks 1502, 1503 and vertically aligned edge marks 1504, 1505, 1506, 1507. Horizontally aligned edge marks 1502, 1503 include an upper horizontal edge mark 1502 and a lower horizontal edge mark 1503. Vertically aligned edge marks 1504, 1505, 1506, 1507 include a center vertical edge mark 1505, an upper vertical edge mark 1504, a lower vertical edge mark 1507, and a non-center vertical edge mark 1506.

[0226] Figure 16 1504, 1505, 1506, 1507. RA measurements are obtained for a process performed on a batch of substrates according to known techniques. For the first substrate in the batch, as shown by RA 0, RA measurements are obtained from all horizontally aligned edge markers 1502, 1503 and vertically aligned edge markers 1504, 1505, 1506, 1507. For each subsequent substrate in the batch, as shown by RA 1 through RAN, RA measurements are obtained from all horizontally aligned edge markers 1502, 1503 and at least the center vertical edge marker 1505.

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

[0228] Figure 17 An alternative technique for obtaining RA measurements for a process performed on a batch of substrates according to the present embodiment is shown. 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 markers 1502, 1503 and the vertically aligned edge markers 1504, 1505, 1506, 1507. For each subsequent substrate in the batch, as shown by RA 1 through RAN, RA measurements are obtained only from some or all of the horizontally aligned edge markers 1502, 1503. Thus, the central vertical edge marker 1505 is measured only for the first substrate and not for subsequent substrates.

[0229] The RA measurement for the first substrate can be fed into the reticle heating model and used to determine the overall deformed shape of the reticle, including the effects of the shape of the reticle platform 200 and the clamping to the reticle platform 200. The same modeled deformation of the clamping effect is then used for the remaining substrates in the batch. Using the same clamping effect model for each substrate in a batch is suitable 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. Therefore, the clamping effect remains essentially constant while processing a batch of substrates.

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

[0231] Advantageously, this embodiment increases the processing rate of substrates because fewer RA measurements are required. Additionally, this embodiment avoids 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 a reticle deformation model to determine the deformation caused by the clamping effect.Process corrections can then be determined in dependence on the determined deformation to at least partially compensate for the deformation.

[0233] Embodiments include a reticle deformation model that includes a reticle heating model. Specifically, the RA measurement obtained in this embodiment can be used by the reticle heating model described earlier according to any of the other embodiments described herein. The RA measurement 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 deformation of the reticle shape caused by clamping the reticle with a reticle holder.The determined deformation can then be at least partially compensated.

[0235] As described earlier, the reticle is secured to the reticle stage 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] Reticle deformation caused by static clamping force can be determined once and then compensated. However, a potential problem is that the clamping force holding the reticle is not static. In other words, the clamping force can vary over time, and the resulting deformation of the reticle shape can therefore vary over time. Temporal variations in clamping force can be caused, for example, by frictional stresses caused by the locking between the reticle and reticle stage 200. Substantial variations in clamping force can occur over a period of approximately 4 to 8 hours and, if not compensated, can increase overlay error by approximately 2 nm.

[0237] Due to the temporal variation in reticle deformation caused by clamping forces, known techniques frequently measure overall reticle deformation so that reticle deformation can be compensated. Specifically, known techniques obtain RA measurements and edge mark measurements of the reticle for each substrate being processed using the reticle. The RA measurements and edge mark measurements are then used to model the deformation of each substrate. Application corrections are then applied to compensate for the determined deformation.

[0238] A problem with the known technology is that the time required to obtain the RA measurement and the edge mark measurement reduces the overall productivity of the lithography system. Any inaccuracy in each edge mark measurement is also a source of error. Obtaining the edge mark measurement also reduces the performance of the resist coating on the substrate W.

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

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

[0241] In this embodiment, the deformation of the reticle caused by the clamping force is determined in a manner that does not require edge mark measurements for each substrate. The overall deformation of the reticle 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 mode caused by the clamping force. The determined deformation mode can be used to determine the reticle deformation caused by the clamping force and determine appropriate process corrections to at least partially compensate for the resulting reticle deformation. Advantageously, this embodiment increases production throughput due to the need for fewer edge measurements. Other problems experienced with known techniques can also be avoided or reduced.

[0242] When performing a photolithography process to form features on a substrate, the shape of the reticle may deform due to both heating effects and the clamping force applied by the reticle clamp. However, when the reticle is properly adjusted and first loaded onto the reticle stage, it experiences substantially no reticle heating effects. In other words, when a cold reticle is first used, it experiences substantially no reticle heating effects. While deformation due to reticle heating effects is substantially absent, the reticle clamping force and the inherent deformation caused by the cold state of the reticle may be the primary contributors to overall reticle deformation.

[0243] The effects of overall reticle deformation can be measured by inspecting features formed on the substrate. Specifically, features formed on the substrate are inspected using metrology equipment. The metrology equipment 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 device is configured to determine one or more performance indicators when using a cold reticle. Therefore, the substantial contributions to the reticle deformation measured by the one or more performance indicators are the reticle deformation caused by the clamping force and the inherent deformation resulting from the cold state of the reticle. A deformation pattern representing the overall reticle deformation can be determined based on the one or more performance indicators. The deformation pattern can be determined using various known techniques, such as PCA analysis, singular value decomposition, and / or other techniques that can be algorithmically implemented.

[0245] The clamping-induced deformation pattern can be determined based on the deformation pattern determined from one or more performance indicators and predetermined knowledge of an inherent deformation pattern that exists in a cold state of the reticle. The inherent deformation pattern that exists in a cold state of the reticle can be obtained from a library. The inherent deformation pattern that exists in a cold state of the reticle can include data regarding an expected shape and / or deformation of the reticle when the reticle is unclamped and has been appropriately temperature-conditioned so that it is in a cold state.

[0246] Determining clamping-induced deformation allows prediction of the overall deformation resulting from using a cold reticle before performing a lithography process with the reticle. The overall deformation can be predicted based on previously determined clamping-induced deformation and knowledge of the cold state of the reticle to be used. Process corrections can then be made to at least partially compensate for the predicted overall deformation. Determination and application of process corrections can be performed online.

[0247] The determination of clamping-induced deformation patterns can rely on measurements of multiple reticles, each in a cold state. Specifically, when processing multiple batches of substrates, the first use of a reticle in each batch can be a cold reticle. For each use of a cold reticle, the above techniques can be used to determine clamping-induced deformation. The prediction of the clamping-induced deformation can be based on multiple previously determined clamping-induced deformations.

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

[0249] According to this embodiment, when processing a batch of substrates, the deformation of the reticle due to the clamping effect is determined based on the clamping-induced deformation pattern that can be obtained as described above. The clamping-induced deformation is thus calculated based on one or more previously used reticles in a cold state. Using the same recently determined clamping-induced deformation for the entire batch of substrates is suitable because the processing time for a batch can be several minutes, while a substantial change in the clamping 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, and the determined overall deformation of the mask can include all of the determination of the mask deformation induced by heating, the expected deformation of the mask in a cold state, and the determination of the deformation caused by clamping forces.

[0251] Advantageously, the present embodiments provide a model with a pattern-based determination of the clamping effect on the reticle. The techniques of the embodiments can be applied online to predict changes in the deformation of the reticle. The embodiments avoid the need for online edge mark measurements of each substrate in a batch. Because the model is pattern-based, the modal deformation shape can be tuned based on the specific properties of the reticle and / or reticle fixture and / or the way the reticle and / or reticle fixture is used. For example, the modal deformation model can be applied to different reticle layouts. The density of the deformation measurements can also be varied, as may be suitable for tuning the determination of parameters used to correct for the deformation.

[0252] This embodiment also allows variations and drifts in the clamping force to be measured and monitored. This provides useful performance information about the reticle clamp.

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

[0254] Figure 18 is a flow chart of a method according to a first embodiment.

[0255] In step 1801, the method starts.

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

[0257] In step 1805 , reticle heating calibration (RHC) data including reticle shape data and corresponding reticle alignment (RA) measurement data are obtained at different reticle temperatures.

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

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

[0260] In step 1811, the operation of a lithography process using the reticle is controlled in dependence on the modeled shape and / or deformation.

[0261] In step 1813, the method ends.

[0262] Figure 19 is a flow chart of a method according to the second embodiment.

[0263] In step 1901, the method starts.

[0264] In step 1903, a reticle heating model is initialized based on reference data of the reticle in a cold state and first reticle alignment measurements of the reticle when the reticle is used in a lithography process performed on a first batch of substrates.

[0265] In step 1905, the state of the reticle heating model is updated while performing a photolithography process on the first batch of substrates.

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

[0267] In step 1909 , reticle transport data depending on the transport of the reticle is generated.

[0268] In step 1911, a determination is made whether the reticle is in a hot state or a cold state, dependent upon the reticle transport data and prior to using the reticle in a lithography process performed on a second batch of substrates.

[0269] In step 1913, the operation of a lithography process using the reticle is controlled in dependence on the modeled shape and / or deformation.

[0270] In step 1915, the method ends.

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

[0272] In step 2001, the method starts.

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

[0274] In step 2005, a state of a reticle heating model is updated while performing a photolithography 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 relying on the reticle process data and the known thermal properties of the reticle.

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

[0278] In step 2013 , the operation of a lithography process using the reticle is controlled in dependence on the modeled shape and / or deformation.

[0279] In step 2015, the method ends.

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

[0281] In step 2101, the method starts.

[0282] In step 2103 , before performing a photolithography process on a first substrate in a batch of substrates, performing reticle alignment RA measurement using a first plurality of edge markers of the reticle, wherein the plurality of edge markers are arranged on a first pair of parallel edges of the reticle.

[0283] In step 2105 , before performing a photolithography process on the first substrate, RA measurement is 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 and the second pair of parallel edges are orthogonal to each other.

[0284] In step 2107, a determination is made of the shape and / or deformation of the mask based on the RA measurements of the first and second edge markers using a mask deformation model, such that the lithography process performed on the first substrate is controlled based on the determined shape and / or deformation.

[0285] In step 2109 , before performing a photolithography process on a second substrate in the batch of substrates, an additional RA measurement is performed using only the first plurality of edge markers.

[0286] In step 2111 , deformation of the reticle when performing the lithography process on the second substrate is determined by a reticle deformation model based on both the additional RA measurement and the RA measurement 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 in dependence 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 photolithography process is performed on the first substrate using the mask in a cold state.

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

[0293] In step 2207, a clamping-induced deformation mode of the reticle is determined depending on one or more performance indicators.

[0294] In step 2209 , process corrections for the lithography process performed on the second substrate are determined and applied in dependence on the determined clamping-induced deformation pattern.

[0295] In step 2211, the method ends.

[0296] Embodiments include numerous modifications and variations of the above-described techniques.

[0297] In all of the above first to fifth embodiments, the mask can be a reference Figures 1 to 10 Reticle 300 is depicted. Embodiments also encompass different types of reticles being used.

[0298] In all the above first to fifth embodiments, the mask holder may be a reference Figures 1 to 10The depicted fixture 250. Embodiments also encompass different types of reticle fixtures being used.

[0299] In all the above first to fifth embodiments, the mask stage can be a reference Figures 1 to 10 Reticle platform 200 is depicted. Embodiments also include different types of reticle platforms being used.

[0300] In all the above first to fifth embodiments, the mask conveying device may be a reference Figures 1 to 10 Reticle transport apparatus 402 is depicted. Embodiments also include different types of reticle transport apparatus being used.

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

[0302] In all of the above first to fifth embodiments, the photolithography system may be a reference Figures 1 to 10 The embodiments also include different types of lithography systems being used.

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

[0304] 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 in .

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

[0306] Although specific reference may be made herein to the use of lithographic equipment in IC manufacturing, it should be understood that the lithographic equipment described herein may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, 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" herein may be considered synonymous with the more general terms "substrate" or "target portion," respectively. The substrates referred to herein may be processed before or after exposure 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. Where applicable, the disclosure herein may be applied to these and other substrate processing tools. In addition, a substrate may be processed more than once, for example to produce a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already includes multiple processed layers.

[0307] While the above may have specifically referenced the use of aspects in the context of optical lithography, it should be understood that the aspects can 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 a patterning device defines the pattern formed on a substrate. The topography of the patterning device can be pressed into a resist layer supplied to a substrate, where the resist is cured by applying 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 is to be understood that the phraseology or terminology herein is for the purpose of description and not limitation, so that the phraseology or terminology of this specification should be interpreted by those skilled in the relevant art in light of the teachings herein.

[0309] The term "substrate" as used herein describes a material onto which a layer of material is added. In some aspects, the substrate itself can be patterned, and the material added on top of the substrate can also be patterned, or the material can 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 normally encountered in the art will be apparent to those skilled in the relevant art and are within the spirit and scope of the present disclosure.

[0311] While specific reference may be made herein to the use of the apparatus and / or system in IC manufacturing, it should be clearly understood that such apparatus and / or system has many other possible applications. For example, it may be used in the manufacture of integrated optical systems, guidance and detection 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 considered to be replaced by the more general terms "mask," "substrate," and "target portion," respectively.

[0312] While certain aspects have been described above, it will be appreciated that the aspects may be practiced otherwise than as described. The description is not intended to limit the scope of the claims.

[0313] It should be understood that the Detailed Description section, rather than the Summary and Abstract sections, is intended to be used to interpret the scope of the claims. The Summary and Abstract sections may set forth one or more, but not all, exemplary aspects contemplated by the inventors, and thus are not intended to limit the aspects and appended claims in any way.

[0314] Aspects have been described above with reference to functional building blocks that illustrate the implementation of specified functions and relationships of the functions. The boundaries of these functional building blocks have been arbitrarily defined herein for ease of description. Alternative boundaries may be defined so long as the specified functions and relationships of the functions are appropriately performed.

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

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

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

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

[0319] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0320] In order to model the shape and / or deformation of the mask, the computer system is configured to:

[0321] obtaining initial reference shape data representing the shape of the mask;

[0322] Obtaining reticle heating calibration (RHC) data including reticle shape data and corresponding reticle alignment (RA) measurement data at different reticle temperatures;

[0323] generating calibrated reference shape data relying on the initial reference shape data, the RHC data, and the RA measurements; and

[0324] The shape and / or deformation of the reticle is modeled relying on calibrated reference shape data.

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

[0326] obtaining 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] obtaining a second data set including reticle shape data and corresponding RA measurement data at a different reticle temperature 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] The RHC data is generated in dependence on the first data set and the second data set.

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

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

[0331] 5. The computer system of any of aspects A1 to A4, wherein the calibrated reference shape data relies 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 of any of clauses A1 to A5, wherein the calibrated reference shape data is dependent upon a determination of a stress-reduced state of the reticle.

[0333] 7. A method comprising:

[0334] Modeling the shape and / or deformation of the reticle; and

[0335] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0336] Modeling the shape and / or deformation of the mask includes:

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

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

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

[0340] The shape and / or deformation of the reticle is modeled relying on calibrated reference shape data.

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

[0342] obtaining 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;

[0343] obtaining a second data set including reticle shape data and corresponding RA measurement data at a different reticle temperature 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

[0344] The RHC data is generated in dependence on the first data set and the second data set.

[0345] 9. The method of aspect A8, wherein the RHC data is determined relying on a comparison of the first data set with the second data set.

[0346] 10. The method of any one of clauses A7 to A9, wherein the calibrated reference shape data relies on a determination of the shape of the reticle when the reticle is in a cold state.

[0347] 11. The method of any of clauses A7 to A10, wherein the calibrated reference shape data relies 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.

[0348] 12. The method of any of clauses A7 to A11, wherein the calibrated reference shape data relies on a determination of a stress-reduced state of the reticle.

[0349] 13. A system comprising:

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

[0351] photolithography equipment;

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

[0353] 14. A device manufacturing method using a photolithography 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 of any one of aspects A7 to A12.

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

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

[0357] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0358] The computer system is configured to:

[0359] initializing the reticle heating model based on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle when the reticle is used in a lithography process performed on a first batch of substrates;

[0360] updating a state of the reticle heating model while performing the photolithography process on the first batch of substrates;

[0361] storing a current state of the reticle heating model after the lithography process has been performed on the first batch of substrates;

[0362] generating reticle transport data dependent on transport of the reticle;

[0363] Determining whether the reticle is in a hot state or a cold state prior to using the reticle in a lithography process performed on a second batch of substrates in dependence on the reticle transport data;

[0364] If it is determined that the reticle is in the thermal state, configuring a starting state of the reticle heating model for a lithography process performed on the second batch of substrates in dependence on the stored state of the reticle heating model; and

[0365] If it is determined that the reticle is in the cold state, the reticle heating model is reinitialized when processing the second batch of substrates based on reference data of the reticle in the cold state and the first reticle alignment measurement of the reticle.

[0366] 2. The computer system of clause B1, wherein the computer system is further configured to determine the reticle temperature in dependence on the reticle transport data.

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

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

[0369] 4. The computer system of any one of aspects B1 to B3, wherein the reticle feed data comprises one or more of:

[0370] Location data describing the location where the mask is located or has been located;

[0371] Time data describing how long the reticle has been at each location and / or when each lithography process performed using the reticle begins and ends;

[0372] thermal data describing the temperature at each location where the reticle was positioned; and

[0373] Data regarding thermal properties of the reticle at each location.

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

[0375] 6. A method comprising:

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

[0377] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0378] The method comprises:

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

[0380] updating a state of the reticle heating model while performing the photolithography process on the first batch of substrates;

[0381] storing a current state of the reticle heating model after the lithography process has been performed on the first batch of substrates;

[0382] generating reticle transport data dependent on transport of the reticle;

[0383] Determining whether the reticle is in a hot state or a cold state prior to using the reticle in a lithography process performed on a second batch of substrates in dependence on the reticle transport data;

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

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

[0386] 7. The method of clause B6, further comprising determining the reticle temperature in dependence on the reticle transport data.

[0387] 8. The method of clause B7, wherein the reticle is determined to be in the hot state if the determined reticle temperature is above a threshold; and

[0388] If the determined reticle temperature is lower than a threshold, it is determined that the reticle is in a cold state.

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

[0390] Location data describing the location where the mask is located or has been located;

[0391] Time data describing how long the reticle has been at each location and / or when each lithography process performed using the reticle begins and ends;

[0392] thermal data describing the temperature at each location where the reticle was positioned; and

[0393] Data regarding thermal properties of the reticle at each location.

[0394] 10. The method of 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] photolithography equipment;

[0398] Wherein the computer system is configured to control the operation of the lithographic apparatus.

[0399] 12. A device manufacturing method using a photolithography 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 lithographic apparatus according to the method of any one of aspects B6 to B10.

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

[0402] 1. A computer system, the computer system being configured to:

[0403] using the reticle heating model to determine the shape and / or deformation of the reticle; and

[0404] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0405] The computer system is configured to:

[0406] initializing the reticle heating model based on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle when the reticle is used in a lithography process performed on a batch of substrates;

[0407] updating a state of the reticle heating model while performing the photolithography process on the batch of substrates;

[0408] Generate mask process data;

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

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

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

[0412] detecting whether a track timing anomaly has occurred by relying on the mask process data;

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

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

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

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

[0417] It is determined that an unplanned change has occurred in the operation of a portion of a lithography system used to perform a lithography process using the reticle.

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

[0419] The determination that a long track timing anomaly has occurred is based on a temperature change of the reticle caused by the track timing anomaly being higher than a threshold.

[0420] 5. The computer system of aspect C4 as dependent upon aspect C2, wherein determining that a short track timing anomaly has occurred is dependent on a temperature change of the reticle caused by the track timing anomaly being less than a threshold value.

[0421] 6. The computer system of any one of clauses C1 to C5, wherein the reticle process data comprises one or more of:

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

[0423] Data on the dose of each exposure; and

[0424] Data regarding any processes that affect properties of the reticle while the reticle remains clamped to a reticle stage.

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

[0426] 8. A method comprising:

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

[0428] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0429] The method comprises:

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

[0431] updating a state of the reticle heating model while performing the photolithography process on the batch of substrates;

[0432] Generate mask process data;

[0433] determining that a long track timing anomaly has occurred relying on the reticle process data and known thermal properties of the reticle; and

[0434] In response to determining that a long track timing anomaly has occurred, the reticle heating model is reconfigured to a same state initialization state used when starting a photolithography process on the batch of substrates.

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

[0436] detecting whether a track timing anomaly has occurred by relying on the mask process data;

[0437] determining that a short track timing anomaly has occurred relying 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, continuing to use the reticle heating model based on a state of the reticle heating model when the track timing anomaly was detected.

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

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

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

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

[0443] The determination that a long track timing anomaly has occurred is based on a temperature change of the reticle caused by the track timing anomaly being higher than a threshold.

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

[0445] 13. The method of any one of clauses C8 to C12, wherein the reticle process data comprises one or more of:

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

[0447] Data on the dose of each exposure; and

[0448] Data regarding any processes that affect properties of the reticle while the reticle remains clamped to the reticle stage.

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

[0450] 15. A system comprising:

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

[0452] photolithography equipment;

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

[0454] 16. A device manufacturing method using a photolithography 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 lithographic apparatus according to the method of any one of clauses C8 to C13.

[0456] Embodiments include the following fourth set of numbered aspects:

[0457] 1. A computer system, the computer system being configured to:

[0458] determining a shape and / or deformation of the reticle using a reticle deformation model; and

[0459] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0460] The computer system is configured to:

[0461] Before performing a photolithography process on a first substrate in a batch of substrates, performing a reticle alignment (RA) measurement using a first plurality of edge markers of the reticle, wherein the plurality of edge markers are arranged on a first pair of parallel edges of the reticle;

[0462] Before performing the photolithography process on the first substrate, performing RA measurement using a second plurality of edge markers of the mask, wherein the plurality of edge markers are arranged on a second pair of parallel edges of the mask and the first pair of parallel edges and the second pair of parallel edges are orthogonal to each other;

[0463] determining a shape and / or deformation of the reticle based on the RA measurements of the first and second edge marks using the reticle deformation model, so as to control a lithography process performed on the first substrate based on the determined shape and / or deformation;

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

[0465] The deformation of the reticle when performing a lithography process on the second substrate is determined by the reticle deformation model relying on both the further RA measurement and an RA measurement obtained before performing a lithography process on the first substrate.

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

[0467] performing RA measurement using only the first plurality of edge markers between performing a photolithography process on two consecutive substrates in the batch of substrates; and

[0468] The deformation of the reticle when performing a lithography process on each substrate is determined by the reticle deformation model relying on both the most recently performed RA measurement and the RA measurement obtained before performing a lithography process on the first substrate.

[0469] 3. The computer system of clause D1 or D2, wherein the reticle deformation model is configured to determine clamping-induced reticle deformation before performing a photolithography process on the first substrate; and

[0470] The same determined clamping-induced reticle deformation is used in all substrates of the batch.

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

[0472] 5. A method comprising:

[0473] determining a shape and / or deformation of the reticle using a reticle deformation model; and

[0474] controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation;

[0475] The method comprises:

[0476] Before performing a photolithography process on a first substrate in a batch of substrates, performing a reticle alignment (RA) measurement using a first plurality of edge markers of the reticle, wherein the plurality of edge markers are arranged on a first pair of parallel edges of the reticle;

[0477] Before performing the photolithography process on the first substrate, performing RA measurement using a second plurality of edge markers of the mask, wherein the plurality of edge markers are arranged on a second pair of parallel edges of the mask and the first pair of parallel edges and the second pair of parallel edges are orthogonal to each other;

[0478] determining a shape and / or deformation of the reticle based on the RA measurements of the first and second edge marks using the reticle deformation model, so as to control a lithography process performed on the first substrate based on the determined shape and / or deformation;

[0479] Before performing a photolithography process on a second substrate in the batch of substrates, performing an additional RA measurement using only the first plurality of edge markers; and

[0480] The deformation of the reticle when performing a lithography process on the second substrate is determined by the reticle deformation model relying on both the further RA measurement and an RA measurement obtained before performing a lithography process on the first substrate.

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

[0482] performing RA measurement using only the first plurality of edge markers between performing a photolithography process on two consecutive substrates in the batch of substrates; and

[0483] The deformation of the reticle when performing a lithography process on each substrate is determined by the reticle deformation model relying on both the most recently performed RA measurement and the RA measurement obtained before performing a lithography process on the first substrate.

[0484] 7. The method of clause D5 or D6, wherein the reticle deformation model determines clamping-induced reticle deformation before performing a lithography process on the first substrate; and

[0485] The same determined clamping-induced reticle deformation is used in all substrates of the batch.

[0486] 8. The method of any one of aspects D5 to D7, wherein the method comprises: incorporating clamping-induced reticle deformation in an initial state of the reticle heating model.

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

[0488] photolithography equipment;

[0489] The computer system is configured to control the operation of the lithographic apparatus.

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

[0491] 11. 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 of any one of aspects D5 to D8.

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

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

[0494] controlling a photolithography process performed on a first substrate using a mask in a cold state;

[0495] determining one or more performance indicators of the lithography process based on an inspection of the first substrate;

[0496] determining a clamping-induced deformation mode of the reticle in dependence upon one or more performance indicators; and

[0497] Application of process corrections to a lithographic process performed on the second substrate is determined and controlled in dependence on the determined clamping-induced deformation pattern.

[0498] 2. The computer system of clause E1, wherein the one or more performance indicators are determined relying on measurements of properties of features formed on the first substrate by the photolithographic process.

[0499] 3. The computer system of aspects E1 or E2, wherein the computer system is configured to determine the clamping-induced deformation pattern by:

[0500] determining a deformation mode of overall reticle deformation in dependence upon the one or more performance indicators;

[0501] obtaining data regarding an expected deformation pattern of the reticle when the reticle is in a cold state when not clamped; and

[0502] The clamping-induced deformation pattern is determined depending on the determined deformation pattern of the overall reticle deformation and the expected deformation pattern of the reticle in a cold state when the reticle is unclamped.

[0503] 4. The computer system of 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 of any one of aspects E1 to E4, wherein the computer system is configured to determine, for each of a plurality of batches of substrates, a clamping-induced deformation pattern of the reticle in a cold state, such that for each batch of substrates, a clamping-induced deformation pattern of the reticle used is determined;

[0505] Wherein the computer system is configured to determine and control application of process corrections to a lithographic process in dependence upon a plurality of determinations of clamping-induced deformation patterns.

[0506] 6. A method comprising:

[0507] performing a photolithography process on the first substrate using the mask in a cold state;

[0508] determining one or more performance indicators of the lithography process based on an inspection of the first substrate;

[0509] determining a clamping-induced deformation mode of the reticle in dependence upon one or more performance indicators; and

[0510] Process corrections for the photolithographic process performed on the second substrate are determined and applied in dependence on the determined clamping-induced deformation pattern.

[0511] 7. The method of clause E6, wherein the one or more performance indicators are determined relying on measurements of properties of features formed on the first substrate by the photolithographic process.

[0512] 8. The method of aspect E6 or E7, wherein determining the clamping-induced deformation mode comprises:

[0513] determining a deformation mode of overall reticle deformation in dependence upon the one or more performance indicators;

[0514] obtaining data regarding an expected deformation pattern of the reticle when the reticle is in a cold state when not clamped; and

[0515] The clamping-induced deformation pattern is determined depending on the determined deformation pattern of the overall reticle deformation and the expected deformation pattern of the reticle in a cold state when the reticle is unclamped.

[0516] 9. The method of 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 of a plurality of batches of substrates using a reticle in a cold state, such that for each batch of substrates a clamping-induced deformation pattern of the reticle used is determined;

[0518] Therein, process corrections applied to the lithographic process are determined relying on multiple determinations of clamping-induced deformation patterns.

[0519] 11. A system comprising:

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

[0521] photolithography equipment;

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

[0523] 12. A device manufacturing method using a photolithography 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 of any one of aspects E6 to E10.

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

Claims

1. A computer system configured to determine a shape and / or deformation of a reticle using a reticle heating model; and controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation; The computer system is configured to: initializing the reticle heating model based on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle when the reticle is used in a lithography process performed on a first batch of substrates; updating a state of the reticle heating model while performing the photolithography process on the first batch of substrates; storing a current state of the reticle heating model after the lithography process has been performed on the first batch of substrates; generating reticle transport data dependent on transport of the reticle; Determining whether the reticle is in a hot state or a cold state prior to using the reticle in a lithography process performed on a second batch of substrates in dependence on the reticle transport data; If it is determined that the reticle is in the thermal state, configuring a starting state of the reticle heating model for a lithography process performed on the second batch of substrates in dependence on the stored state of the reticle heating model; as well as If it is determined that the reticle is in the cold state, the reticle heating model is reinitialized when processing the second batch of substrates based on reference data of the reticle in the cold state and the first reticle alignment measurement of the reticle.

2. The computer system according to claim 1, wherein: The computer system is further configured to determine the reticle temperature in dependence upon the reticle transport data.

3. The computer system according to claim 2, wherein: The computer system is configured to determine that the reticle is in the thermal state if the determined reticle temperature is above a threshold; and The computer system is configured to determine that the reticle is in a cold state if the determined reticle temperature is below a threshold.

4. The computer system according to claim 1, wherein: The reticle transport data includes one or more of the following: Location data describing the location where the mask is located or has been located; Time data describing how long the reticle has been at each location and / or when each lithography process performed using the reticle begins and ends; thermal data describing the temperature at each location where the reticle was positioned; as well as Data regarding thermal properties of the reticle at each location.

5. The computer system according to claim 1, wherein: The first batch of substrates includes the same substrates as the second batch of substrates.

6. A method comprising: using a reticle heating model to determine a shape and / or deformation of the reticle; and controlling the operation of a lithographic process using the reticle in dependence upon the modeled shape and / or deformation; The method comprises: initializing the reticle heating model based on reference data of the reticle in a cold state and a first reticle alignment measurement of the reticle when the reticle is used in a lithography process performed on a first batch of substrates; updating a state of the reticle heating model while performing the photolithography process on the first batch of substrates; storing a current state of the reticle heating model after the lithography process has been performed on the first batch of substrates; generating reticle transport data dependent on transport of the reticle; Determining whether the reticle is in a hot state or a cold state prior to using the reticle in a lithography process performed on a second batch of substrates in dependence on the reticle transport data; If it is determined that the reticle is in the thermal state, configuring a starting state of the reticle heating model for a lithography process performed on the second batch of substrates in dependence on the stored state of the reticle heating model; and If it is determined that the reticle is in the cold state, the reticle heating model is reinitialized when processing the second batch of substrates based on reference data of the reticle in the cold state and the first reticle alignment measurement of the reticle. The method of claim 6 , further comprising determining the reticle temperature in dependence on the reticle transport data.

8. The method according to claim 7, wherein: determining that the reticle is in the hot state if the determined reticle temperature is above a threshold; and The reticle is determined to be in the cold state if the determined reticle temperature is below a threshold.

9. The method according to claim 6, wherein: The reticle transport data includes one or more of the following: Location data describing the location where the mask is located or has been located; Time data describing how long the reticle has been at each location and / or when each lithography process performed using the reticle begins and ends; thermal data describing the temperature at each location where the reticle was positioned; as well as Data regarding thermal properties of the reticle at each location.

10. The method according to claim 6, wherein: The first batch of substrates includes the same substrates as the second batch of substrates.

11. A system comprising: The computer system according to claim 1; and photolithography equipment; Wherein the computer system is configured to control the operation of the lithographic apparatus.

12. A device manufacturing method using a photolithography process, the device manufacturing method comprising the method according to claim 6.

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 of claim 6.

Images