A method, system and storage medium for improving wafer measurement accuracy

Abstract

The present application provides a method, system and storage medium for improving wafer measurement accuracy, the method comprising: generating a predefined measurement pattern in measurement software based on a design pattern; simulating based on an optical simulation model to obtain a simulation pattern, the simulation pattern representing a pattern on a mask plate projected onto a wafer, the pattern on the mask plate being determined based on the design pattern; obtaining the similarity between the predefined measurement pattern and the simulation pattern; adjusting the morphological parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range; measuring the wafer based on the adjusted predefined measurement pattern to obtain measurement data. The present application scheme adjusts the morphological parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range, so as to maximize the consistency between the predefined measurement pattern and the actual pattern projected onto the wafer, thereby improving the accuracy of wafer measurement.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and more particularly to a method, system and storage medium for improving wafer measurement accuracy. Background Art

[0002] In the photolithography process, the pattern on the mask is projected onto the photoresist layer (photoresist) through the exposure system. The pattern on the photoresist layer is not completely consistent with the pattern on the mask, and there is a problem of pattern distortion. In order to overcome the optical image distortion, the optical proximity correction (OPC) technology is introduced to compensate for it, so that the same pattern as the designed pattern can be obtained on the wafer, even if the pattern on the photoresist layer on the wafer is consistent with the pattern on the mask.

[0003] OPC technology includes rule-based OPC (RB-OPC) technology and model-based OPC (MB-OPC) technology. Among them, model-based OPC technology is widely used because of its more accurate correction effect.

[0004] In the model-based OPC technology, the most critical link is the establishment of an optical simulation model, in which it is necessary to simulate the changes in the graphics by establishing an optical simulation model, simulate the spatial image contour according to the model, iteratively correct the edge of the mask graphics, and make the simulated contour of the mask graphics consistent with the target contour, so as to obtain the same graphics as the designed graphics on the wafer.

[0005] The establishment of an optical simulation model is closely related to measurement data. However, in the related art, there are a large number of measurement failures in the process of collecting measurement data, which leads to a decrease in the accuracy of the optical simulation model and a long modeling cycle of the optical simulation model.

[0006] Improvements are therefore needed to at least partially address the above-mentioned problems. Summary of the invention

[0007] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0008] In view of the existing problems, the present application provides a method for improving wafer measurement accuracy, including:

[0009] Generate predefined measurement graphics in the measurement software based on the design graphics;

[0010] Performing simulation based on the optical simulation model to obtain a simulation graph, wherein the simulation graph represents a graph obtained by projecting a graph on the mask onto the wafer, wherein the graph on the mask is determined based on the design graph;

[0011] Obtaining the similarity between the predefined measurement graph and the simulation graph;

[0012] Adjusting the topographic parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range;

[0013] The wafer is measured based on the adjusted predefined measurement pattern to obtain measurement data.

[0014] Exemplarily, obtaining the similarity between the predefined measurement graph and the simulation graph includes:

[0015] The similarity between the predefined measurement pattern and the simulation pattern is obtained based on the morphology function of the predefined measurement pattern and the morphology function of the simulation pattern, wherein the morphology function of the predefined measurement pattern is obtained based on the morphology parameters of the predefined measurement pattern, and the morphology function of the simulation pattern is obtained based on the optical simulation model.

[0016] Exemplarily, the similarity between the predefined measurement pattern and the simulation pattern is obtained based on the topography function of the predefined measurement pattern and the topography function of the simulation pattern by the following formula:

[0017]

[0018] Wherein, C represents the similarity between the predefined measurement pattern and the simulation pattern, S represents the topography function of the predefined measurement pattern, and W represents the topography function of the simulation pattern.

[0019] Exemplarily, the topographic parameters of the predefined measurement pattern include at least the grayscale, key dimension, curvature and zoom ratio of the predefined measurement pattern;

[0020] Obtaining a topography function of the predefined measurement pattern based on the topography parameters of the predefined measurement pattern comprises:

[0021] Based on the grayscale, key dimension, radian and zoom ratio of the predefined measurement pattern, a grayscale correlation function, a key dimension correlation function, a radian correlation function and a zoom ratio correlation function of the predefined measurement pattern are obtained respectively;

[0022] Based on the grayscale correlation function, the critical dimension correlation function, the radian correlation function and the zoom factor correlation function of the predefined measurement pattern, the topography function of the predefined measurement pattern is obtained.

[0023] Exemplarily, the similarity between the predefined measurement pattern and the simulation pattern is obtained based on the topography function of the predefined measurement pattern and the topography function of the simulation pattern by the following formula:

[0024]

[0025] Among them, C represents the similarity between the predefined measurement pattern and the simulation pattern, S represents the morphology function of the predefined measurement pattern, G represents the grayscale correlation function of the predefined measurement pattern, CD represents the key dimension correlation function of the predefined measurement pattern, F represents the radian correlation function of the predefined measurement pattern, D represents the scaling factor correlation function of the predefined measurement pattern, and W represents the morphology function of the simulation pattern.

[0026] Exemplarily, before measuring the wafer based on the adjusted predefined measurement pattern, the method further includes the following steps: coating a photoresist layer on the wafer, exposing the photoresist layer using the mask so that the pattern on the mask is projected onto the wafer;

[0027] Measuring the wafer based on the adjusted predefined measurement pattern includes: measuring a critical dimension of a pattern projected onto the wafer based on the adjusted predefined measurement pattern.

[0028] Exemplarily, a critical dimension scanning electron microscope is used to measure the critical dimension of the pattern obtained by projection on the wafer.

[0029] Exemplarily, the measurement data is used to establish an optical simulation model based on optical proximity effect correction technology.

[0030] On the other hand, the present application provides a system for improving wafer measurement accuracy, the system for improving wafer measurement accuracy includes a memory and a processor, the memory stores a computer program executed by the processor, and when the computer program is executed, the processor executes the above-mentioned method for improving wafer measurement accuracy.

[0031] On another aspect, the present application provides a storage medium, on which is stored a computer program executed by a processor, and when the computer program is executed, the processor executes the above-mentioned method for improving wafer measurement accuracy.

[0032] The method, system and storage medium for improving wafer measurement accuracy of the embodiments of the present application can maximize the consistency between the predefined measurement pattern and the actual pattern projected onto the wafer by adjusting the morphological parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range, thereby improving the accuracy of wafer measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following drawings of the present application are used as part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, and are used to explain the principles of the present application. In the drawings:

[0034] Figure 1 A flow chart showing a method for improving wafer measurement accuracy according to a specific embodiment of the present application is shown;

[0035] Figure 2 A schematic structural block diagram of a system for improving wafer measurement accuracy according to a specific embodiment of the present application is shown. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present invention more obvious, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described in the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the protection scope of the present invention.

[0037] In the photolithography process, due to the existence of the optical proximity effect (OPE), the optical image distortion of the obtained pattern will occur, that is, the pattern on the photoresist layer and the pattern on the mask will not be completely consistent. In related technologies, OPC technology is generally used to compensate for the optical proximity effect. Among them, the most critical link of the model-based OPC technology is the establishment of the optical simulation model, which is closely related to the measurement data.

[0038] In the related art, the measurement graphics are generally predefined in the measurement software manually, for example, by manually adjusting the grayscale, critical dimension (CD), curvature, zoom ratio and other parameters of the predefined graphics, wherein the zoom ratio can be represented by opening the frame; however, due to manual errors, there are certain differences between the measurement graphics predefined in the measurement software and the actual measurement target graphics, which ultimately leads to unstable measurement and measurement failure, resulting in reduced accuracy of the optical simulation model and excessively long modeling cycle of the optical simulation model.

[0039] Therefore, in view of the existence of the aforementioned technical problems, the present application proposes a method for improving wafer measurement accuracy, including:

[0040] Generate predefined measurement graphics in the measurement software based on the design graphics;

[0041] Perform simulation based on the optical simulation model to obtain a simulation graphic, which represents a graphic obtained by projecting the graphic on the mask onto the wafer. The graphic on the mask is determined based on the design graphic;

[0042] Obtaining the similarity between the predefined measurement graph and the simulation graph;

[0043] Adjusting the topographic parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range;

[0044] The wafer is measured based on the adjusted predefined measurement pattern to obtain measurement data.

[0045] The method for improving wafer measurement accuracy of the present application adjusts the morphological parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range, so as to maximize the consistency between the predefined measurement pattern and the actual pattern projected on the wafer, thereby improving the accuracy of wafer measurement.

[0046] Below, reference Figure 1 The method for improving wafer measurement accuracy of the present application is described in detail, wherein: Figure 1 A flow chart of a method for improving wafer measurement accuracy according to a specific embodiment of the present application is shown.

[0047] Exemplarily, the method for improving wafer measurement accuracy of the present application includes the following steps:

[0048] First, step S1 is executed to generate a predefined measurement pattern in the measurement software based on the design pattern.

[0049] In one example, the design pattern is a target pattern designed according to design rules and desired to be projected onto a wafer. Ideally, the pattern on the mask is first determined based on the design pattern, and then the pattern on the mask is projected onto the wafer through an exposure system to obtain a pattern on the wafer that is the same as the design.

[0050] In one example, a predefined measurement pattern is used as a reference when actually measuring a wafer, and the predefined measurement pattern has multiple morphological parameters, and the morphological parameters of the predefined measurement pattern are determined based on the morphological parameters of the design pattern, so that the predefined measurement pattern is consistent with the design pattern; wherein the morphological parameters of the predefined measurement pattern can be manually adjusted in the measurement software. Exemplarily, the morphological parameters of the predefined measurement pattern include at least the grayscale, critical dimensions, curvature, and zoom ratio of the predefined measurement pattern, wherein the zoom ratio can be characterized by an open frame. Exemplarily, the measurement software can be any suitable software that can read and adjust the morphological parameters of the predefined measurement pattern, and the present application does not limit this.

[0051] Next, step S2 is executed to perform simulation based on the optical simulation model to obtain a simulation graph, wherein the simulation graph represents a graph obtained by projecting the graph on the mask onto the wafer, and the graph on the mask is determined based on the design graph.

[0052] In one example, the optical simulation model used in the step of obtaining the simulation pattern can be a simple optical simulation model based on the optical proximity effect correction technology, or can also be any suitable optical simulation model that can simulate the exposure process (projecting the pattern on the mask onto the wafer) so that the obtained simulation pattern can represent the pattern obtained by projecting the pattern on the mask onto the wafer. Exemplarily, a photoresist layer is coated on the wafer, and the simulation model represents the pattern obtained by projecting the pattern on the mask onto the photoresist layer on the wafer. Exemplarily, the pattern on the mask is determined based on the design pattern, that is, the pattern on the mask is determined based on the design pattern, so that the pattern projected onto the wafer by the exposure system is substantially the same as the design pattern.

[0053] In one example, due to the problem of graphic distortion during the exposure process, for example, due to the existence of the optical proximity effect during the exposure process, the graphic obtained by projecting the graphic on the mask onto the wafer is inconsistent with the graphic on the mask, that is, it will cause the predefined measurement graphic to be inconsistent with the simulation graphic. If the wafer is measured directly based on the predefined measurement graphic, it is easy to cause measurement failure due to the inconsistency of the graphic.

[0054] Next, step S3 is executed to obtain the similarity between the predefined measurement pattern and the simulation pattern.

[0055] In one example, obtaining the similarity between a predefined measurement figure and a simulation figure includes: obtaining the similarity between the predefined measurement figure and the simulation figure based on the morphology function of the predefined measurement figure and the morphology function of the simulation figure, wherein the morphology function of the predefined measurement figure is obtained based on the morphology parameters of the predefined measurement figure, and the morphology function of the simulation figure is obtained based on the optical simulation model. Exemplarily, the morphology function of the predefined measurement figure can be obtained based on the morphology parameters of the predefined measurement figure by a functional relationship commonly used in the art, and the present application does not limit this. Exemplarily, in the aforementioned step of obtaining the simulation figure, the morphology function of the simulation figure can be obtained based on the optical simulation model at the same time. In other embodiments, the similarity between the predefined measurement figure and the simulation figure can also be obtained by any other suitable method, for example, the similarity between the predefined measurement figure and the simulation figure can be obtained by an intelligent recognition algorithm, and the present application does not limit this.

[0056] Next, step S4 is executed to adjust the topographic parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range.

[0057] In one example, due to the existence of pattern distortion during the exposure process, there is a certain difference between the predefined measurement pattern generated based on the design pattern and the simulation pattern at the beginning. In order to improve the consistency between the predefined measurement pattern and the simulation pattern, it is necessary to adjust the morphological parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range, so that the predefined measurement pattern is more consistent with the actual pattern on the wafer (the actual pattern on the photoresist layer on the wafer), thereby improving the accuracy of wafer measurement. Exemplarily, the preset threshold range can be reasonably set according to actual needs.

[0058] In one example, the similarity between the predefined measurement pattern and the simulation pattern is obtained based on the shape function of the predefined measurement pattern and the shape function of the simulation pattern by the following formula:

[0059]

[0060] Wherein, C represents the similarity between the predefined measurement pattern and the simulation pattern, S represents the morphology function of the predefined measurement pattern, and W represents the morphology function of the simulation pattern.

[0061] It can be seen from the above formula that when the similarity between the predefined measurement graph and the simulation graph is higher, C is closer to 0%, and the similarity between the predefined measurement graph and the simulation graph can be characterized by the degree of proximity between C and 0%; in this embodiment, the preset threshold range is the numerical range of C, and the preset threshold range can be set near 0%, for example, the preset threshold range is -2%-2%, or the preset threshold range can be any other suitable numerical range.

[0062] In one example, the morphological parameters of the predefined measurement pattern at least include the grayscale, critical dimension, radian and zoom ratio of the predefined measurement pattern, and the morphological function of the predefined measurement pattern is obtained based on the morphological parameters of the predefined measurement pattern, including: obtaining the grayscale correlation function, the critical dimension correlation function, the radian correlation function and the zoom ratio correlation function of the predefined measurement pattern based on the grayscale, critical dimension, radian and zoom ratio of the predefined measurement pattern respectively; obtaining the morphological function of the predefined measurement pattern based on the grayscale correlation function, the critical dimension correlation function, the radian correlation function and the zoom ratio correlation function of the predefined measurement pattern. Exemplarily, the grayscale correlation function, the critical dimension correlation function, the radian correlation function and the zoom ratio correlation function of the predefined measurement pattern can be obtained based on the grayscale, critical dimension, radian and zoom ratio of the predefined measurement pattern through the functional relationship commonly used in the art, and the morphological function of the predefined measurement pattern can be obtained based on the grayscale correlation function, the critical dimension correlation function, the radian correlation function and the zoom ratio correlation function of the predefined measurement pattern.

[0063] In one example, the similarity between the predefined measurement pattern and the simulation pattern is obtained based on the shape function of the predefined measurement pattern and the shape function of the simulation pattern by the following formula:

[0064]

[0065] Among them, C represents the similarity between the predefined measurement figure and the simulation figure, S represents the morphology function of the predefined measurement figure, G represents the grayscale correlation function of the predefined measurement figure, CD represents the key dimension correlation function of the predefined measurement figure, F represents the radian correlation function of the predefined measurement figure, D represents the zoom ratio correlation function of the predefined measurement figure, and W represents the morphology function of the simulation figure.

[0066] Similarly, from the above formula, it can be seen that when the similarity between the predefined measurement graph and the simulation graph is higher, C is closer to 0%, and the similarity between the predefined measurement graph and the simulation graph can be characterized by the degree of proximity between C and 0%; in this embodiment, the preset threshold range is the numerical range of C, and the preset threshold range can be set near 0%, for example, the preset threshold range is -2%-2%, or the preset threshold range can be any other suitable numerical range.

[0067] Next, step S5 is executed to measure the wafer based on the adjusted predefined measurement pattern to obtain measurement data. Exemplarily, the adjusted predefined measurement pattern refers to the predefined measurement pattern obtained by adjusting the morphological parameters of the predefined measurement pattern in the aforementioned step S4. Exemplarily, in this step, the actual pattern on the wafer can be measured at the same time.

[0068] In one example, before measuring the wafer based on the adjusted predefined measurement pattern, the following steps are also included: coating a photoresist layer on the wafer, exposing the photoresist layer using a mask so that the pattern on the mask is projected onto the wafer, specifically, the pattern on the mask is projected onto the photoresist layer on the wafer.

[0069] In one example, measuring the wafer based on the adjusted predefined measurement pattern includes: measuring the critical dimensions of the pattern projected on the wafer based on the adjusted predefined measurement pattern, and the measurement data includes the critical dimensions of the pattern projected on the wafer. Exemplarily, a critical dimension scanning electron microscope (CD-SEM, Critical Dimension Scanning Electron Microscope) can be used to measure the critical dimensions of the pattern projected on the wafer.

[0070] In one example, since the morphological parameters of the predefined measurement pattern are adjusted in the aforementioned step S4 so that the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range, the predefined measurement pattern can be kept consistent with the actual pattern projected on the wafer to the greatest extent, so that when the wafer is measured based on the adjusted predefined measurement pattern, the measurement accuracy is higher.

[0071] In one example, the measurement data is used to establish an optical simulation model based on the optical proximity effect correction technology, and the optical simulation model based on the optical proximity effect correction technology is used for the MB-OPC technology. Since the solution of the present application can improve the accuracy of wafer measurement, a large amount of measurement data can be quickly obtained, which can shorten the modeling cycle of the optical simulation model based on the optical proximity effect correction technology and improve the accuracy of the optical simulation model based on the optical proximity effect correction technology. Exemplarily, the measurement data can also be used for the modeling of any other suitable model, which is not limited by the present application.

[0072] So far, the description of the key steps of the method for improving wafer measurement accuracy of the present application has been completed. The complete method may also include other steps, which will not be described one by one here. It is worth mentioning that the order of the above steps can be adjusted without conflict.

[0073] In summary, the method for improving wafer measurement accuracy of the embodiment of the present application can maximize the consistency between the predefined measurement pattern and the actual pattern projected on the wafer by adjusting the morphological parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range, thereby improving the accuracy of wafer measurement. Exemplarily, the measurement data is used to establish an optical simulation model based on the optical proximity effect correction technology, which can shorten the modeling cycle of the optical simulation model based on the optical proximity effect correction technology and improve the accuracy of the optical simulation model based on the optical proximity effect correction technology.

[0074] Combine the following Figure 2 A system 200 for improving wafer measurement accuracy is described according to another aspect of the present application. Figure 2 As shown, the system 200 for improving wafer measurement accuracy may include a memory 210 and a processor 220. The memory 210 stores a computer program executed by the processor 220. When the computer program is executed, the processor 220 executes the aforementioned method 100 for improving wafer measurement accuracy according to the embodiment of the present application. The method 100 for improving wafer measurement accuracy has been described in detail above. Those skilled in the art can understand the structure and operation of the system 200 for improving wafer measurement accuracy in combination with the above. For the sake of brevity, it will not be repeated here.

[0075] In addition, according to an embodiment of the present application, a storage medium is also provided, on which program instructions are stored, and when the program instructions are executed by a computer or a processor, the corresponding steps of the method 100 for improving wafer measurement accuracy of the embodiment of the present application are executed. The storage medium may include, for example, a memory card of a smart phone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disk read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0076] In addition, according to an embodiment of the present application, a computer program is also provided, which can be stored in a cloud or local storage medium. When the computer program is run by a computer or a processor, it is used to execute the corresponding steps of the method 100 for improving wafer measurement accuracy of the embodiment of the present application.

[0077] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present invention thereto. Various changes and modifications may be made therein by one of ordinary skill in the art without departing from the scope and spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as required by the appended claims.

[0078] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0079] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0080] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0081] Similarly, it should be understood that in order to streamline the present invention and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present invention should not be interpreted as reflecting the following intention: the claimed invention requires more features than the features explicitly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present invention.

[0082] Those skilled in the art will understand that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstract and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise explicitly stated, each feature disclosed in this specification (including the accompanying claims, abstract and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0083] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0084] The various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some modules in the article analysis device according to an embodiment of the present invention. The present invention may also be implemented as a device program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program for implementing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such a signal may be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0085] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

[0086] The above is only a specific embodiment of the present invention or an explanation of a specific embodiment. The protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for improving wafer measurement accuracy, characterized in that: The method comprises: Generate predefined measurement graphics in the measurement software based on the design graphics; Performing simulation based on the optical simulation model to obtain a simulation graph, wherein the simulation graph represents a graph obtained by projecting a graph on the mask onto the wafer, wherein the graph on the mask is determined based on the design graph; Obtaining the similarity between the predefined measurement pattern and the simulation pattern, comprising: obtaining the similarity between the predefined measurement pattern and the simulation pattern based on the morphology function of the predefined measurement pattern and the morphology function of the simulation pattern; Adjusting the topographic parameters of the predefined measurement pattern until the similarity between the predefined measurement pattern and the simulation pattern is within a preset threshold range; The wafer is measured based on the adjusted predefined measurement pattern to obtain measurement data, and the measurement data is used to establish an optical simulation model based on optical proximity effect correction technology.

2. The method according to claim 1, characterized in that: A morphology function of the predefined measurement pattern is obtained based on the morphology parameters of the predefined measurement pattern, and a morphology function of the simulation pattern is obtained based on the optical simulation model.

3. The method according to claim 1, characterized in that The similarity between the predefined measurement pattern and the simulation pattern is obtained based on the topography function of the predefined measurement pattern and the topography function of the simulation pattern by the following formula: Wherein, C represents the similarity between the predefined measurement pattern and the simulation pattern, S represents the topography function of the predefined measurement pattern, and W represents the topography function of the simulation pattern.

4. The method according to claim 2, characterized in that: The morphological parameters of the predefined measurement pattern at least include the grayscale, key dimension, curvature and zoom ratio of the predefined measurement pattern; Obtaining a topography function of the predefined measurement pattern based on the topography parameters of the predefined measurement pattern comprises: Based on the grayscale, key dimension, radian and zoom ratio of the predefined measurement pattern, a grayscale correlation function, a key dimension correlation function, a radian correlation function and a zoom ratio correlation function of the predefined measurement pattern are obtained respectively; Based on the grayscale correlation function, the critical dimension correlation function, the radian correlation function and the zoom factor correlation function of the predefined measurement pattern, the topography function of the predefined measurement pattern is obtained.

5. The method according to claim 4, characterized in that The similarity between the predefined measurement pattern and the simulation pattern is obtained based on the topography function of the predefined measurement pattern and the topography function of the simulation pattern by the following formula: Among them, C represents the similarity between the predefined measurement pattern and the simulation pattern, S represents the morphology function of the predefined measurement pattern, G represents the grayscale correlation function of the predefined measurement pattern, CD represents the key dimension correlation function of the predefined measurement pattern, F represents the radian correlation function of the predefined measurement pattern, D represents the scaling factor correlation function of the predefined measurement pattern, and W represents the morphology function of the simulation pattern.

6. The method according to claim 1, before measuring the wafer based on the adjusted predefined measurement pattern, further comprising the following steps: Coating a photoresist layer on the wafer, and exposing the photoresist layer using the mask so that the pattern on the mask is projected onto the wafer; Measuring the wafer based on the adjusted predefined measurement pattern includes: measuring a critical dimension of a pattern projected onto the wafer based on the adjusted predefined measurement pattern.

7. The method according to claim 6, characterized in that The critical dimensions of the projected graphics on the wafer are measured using a critical dimension scanning electron microscope.

8. A system for improving wafer measurement accuracy, characterized in that: The system for improving wafer measurement accuracy includes a memory and a processor, wherein the memory stores a computer program executed by the processor, and when the computer program is executed, the processor executes the method for improving wafer measurement accuracy according to any one of claims 1 to 7.

9. A storage medium, characterized in that: The storage medium stores a computer program executed by a processor, and when the computer program is executed, the processor executes the method for improving wafer measurement accuracy according to any one of claims 1 to 7.

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