Method, system, device, medium and program for verifying an optical proximity correction model

Abstract

Embodiments of the present application provide a kind of optical proximity correction model verification method, system, equipment, medium and program, wherein verification method includes: providing first layout for verifying model, first layout includes target pattern;Provide first optical proximity correction model to be verified and second optical proximity correction model that has completed verification;Using first optical proximity correction model, target pattern is carried out cyclic iteration correction operation, and the test pattern after correction is obtained, wherein cyclic iteration correction operation includes multiple correction stages, multiple correction stages respectively use different mask rule constraint value, and mask rule constraint value is greater than or equal to the minimum pitch value of mask writing;Based on the test pattern after correction, using second optical proximity correction model, first optical proximity correction model is verified.Using the above technical solution, the cross verification between different optical proximity correction models can be realized, the verification efficiency is improved, and the verification cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a verification method, system, device, medium and program for an optical proximity correction model. Background Technology

[0002] In semiconductor manufacturing, as design dimensions continue to shrink, the diffraction effect of light becomes increasingly pronounced, leading to optical image degradation of the final design pattern. The actual lithographic pattern formed is severely distorted relative to the pattern on the mask, ultimately resulting in a difference between the actual pattern formed on the silicon wafer and the design pattern. This phenomenon is called the Optical Proximity Effect (OPE).

[0003] To correct for the optical proximity effect, Optical Proximity Correction (OPC) was developed. With continuous advancements in technology, the accuracy requirements for OPC model correction are increasing. The OPC model needs to precisely correct each pattern to meet process requirements. Generally, the smaller the pattern size and the denser the pattern, the closer it is to the theoretical limit of photolithography, the greater the error in the OPC model. Currently, the main approach is to reduce the error of the OPC model to improve pattern correction accuracy. Correspondingly, this places higher demands on the verification process of the OPC model.

[0004] Currently, the validation process for existing OPC models still needs optimization. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a verification method, system, device, medium and program for optical proximity correction models, which can realize cross-verification between different optical proximity correction models, improve verification efficiency and reduce verification costs.

[0006] This invention provides a method for verifying an optical proximity correction model, comprising: providing a first layout for verifying the model, the first layout including a target graphic; providing a first optical proximity correction model to be verified and a second optical proximity correction model that has been verified, wherein the first optical proximity correction model and the second optical proximity correction model are established based on the same second layout; performing iterative correction operations on the target graphic using the first optical proximity correction model to obtain a corrected test graphic, wherein the iterative correction operations include multiple correction stages, each of the multiple correction stages using different mask rule constraint values, and the mask rule constraint values ​​being greater than or equal to the minimum spacing value of the mask writing; and verifying the first optical proximity correction model using the second optical proximity correction model based on the corrected test graphic.

[0007] This invention provides a verification system for an optical proximity correction model, comprising: a graphic providing module for providing a first layout for verifying the model, the first layout including a target graphic; a model providing module for providing a first optical proximity correction model to be verified and a second optical proximity correction model that has been verified, wherein the first optical proximity correction model and the second optical proximity correction model are established based on the same second layout; a correction module for performing iterative correction operations on the target graphic using the first optical proximity correction model to obtain a corrected test graphic, wherein the iterative correction operations include multiple correction stages, each of the multiple correction stages using different mask rule constraint values, and the mask rule constraint values ​​being greater than or equal to the minimum spacing value of the mask writing; and a verification module for verifying the first optical proximity correction model using the second optical proximity correction model based on the corrected test graphic.

[0008] Accordingly, embodiments of the present invention also provide an electronic device, including at least one memory and at least one processor, wherein the memory stores one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the verification method of the optical proximity correction model described in any embodiment of the present invention.

[0009] Accordingly, embodiments of the present invention also provide a storage medium storing one or more computer instructions, which are used to implement the verification method of the optical proximity correction model described in any embodiment of the present invention.

[0010] Accordingly, embodiments of the present invention also provide a computer program product, including computer instructions, which, when executed by a processor, are used to implement the verification method of the optical proximity correction model described in any embodiment of the present invention.

[0011] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0012] In the verification method of the optical proximity correction model provided in this embodiment of the invention, the second optical proximity correction model has been verified, indicating that the second optical proximity correction model is reliable. The graphic obtained after correcting the target graphic using the second optical proximity correction model can meet the manufacturing requirements. Thus, after performing iterative correction operations on the target graphic using the first optical proximity correction model, a corrected test graphic is obtained. The first optical proximity correction model can then be verified using the second optical proximity correction model. Since the second optical proximity correction model is reliable, and different photomasks are used in each of the multiple correction stages during the iterative correction operation on the target graphic, this method is effective. The rule constraint value ensures that the spacing between the target pattern after optical proximity correction is within a preset range, thereby reducing the error between different models. Furthermore, since both the second and first optical proximity correction models are built based on the same second layout, the differences between models can be further reduced. This improves the accuracy of the second optical proximity correction model in verifying the first optical proximity correction model and enables cross-validation between different optical proximity correction models. Moreover, it eliminates the need to produce additional test masks and collect data on the actual pattern of the physical wafer after photolithography based on the test masks, thus improving verification efficiency and reducing verification costs. Attached Figure Description

[0013] Figure 1 This is a flowchart of a traditional method for obtaining an optical proximity correction model;

[0014] Figure 2 This is a flowchart of a verification method for an optical proximity correction model in an embodiment of the present invention;

[0015] Figure 3 This is a flowchart illustrating a verification method for an optical proximity correction model in an embodiment of the present invention.

[0016] Figure 4 This is a schematic diagram illustrating the principle of verifying an optical proximity correction model after correcting a test pattern using a traditional correction method.

[0017] Figure 5 This is a schematic diagram illustrating the principle of verifying an optical proximity correction model in an embodiment of the present invention;

[0018] Figure 6 This is a functional block diagram of a verification system for an optical proximity correction model in an embodiment of the present invention;

[0019] Figure 7 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0020] As can be seen from the background technology, the verification process of existing OPC models needs to be optimized.

[0021] See Figure 1 The flowchart shown is a traditional method for obtaining an optical proximity correction model, as follows: Figure 1 As shown, the traditional method for obtaining the optical proximity correction model includes the following steps:

[0022] S1 provides a test layout with test graphics;

[0023] S2, using the initial optical proximity correction model, perform optical proximity correction on the test pattern, and manufacture the corresponding first photomask based on the corrected pattern;

[0024] S3, using the first photomask, obtain the first actual exposure pattern formed on the physical wafer, and obtain the critical dimension (CD) of the first actual exposure pattern;

[0025] S4, Fit and validate the initial optical proximity correction model based on the key dimensions of the first actual exposure pattern to obtain the optical proximity correction model;

[0026] S5. Using the optical proximity correction model and taking the minimum spacing value written by the mask as the mask rule constraint value, optical proximity correction is performed on the test pattern and the real design pattern, and the corresponding second mask is manufactured according to the corrected pattern.

[0027] S6, using the second photomask, a second actual exposure pattern formed on the physical wafer is obtained, and the second key dimension of the second actual exposure pattern is acquired;

[0028] S7 uses an optical proximity correction model to simulate exposure on test patterns and real design patterns, obtains simulated exposure patterns, and obtains the third key dimension of the simulated exposure patterns;

[0029] S8, based on the second key dimension of the second actual exposure pattern and the corresponding third key dimension of the simulated exposure pattern, verify the correction performance of the optical proximity correction model, and if the verification is successful, use the current optical proximity correction model as the final optical proximity correction model.

[0030] In the above process, when performing steps S6 and S7, it is necessary to use the second actual exposure pattern formed on the physical wafer to verify the correction performance of the optical proximity correction model, which makes the verification process too long and time-consuming.

[0031] To address the aforementioned technical problems, this invention provides a verification method for an optical proximity correction model, comprising: providing a first layout for verifying the model, the first layout including a target graphic; providing a first optical proximity correction model to be verified and a second optical proximity correction model that has been verified, wherein the first optical proximity correction model and the second optical proximity correction model are established based on the same second layout; performing iterative correction operations on the target graphic using the first optical proximity correction model to obtain a corrected test graphic, wherein the iterative correction operations include multiple correction stages, each of the multiple correction stages employing different mask rule constraint values, and the mask rule constraint values ​​are greater than or equal to the minimum spacing value of the mask writing; and verifying the first optical proximity correction model using the second optical proximity correction model based on the corrected test graphic.

[0032] In the verification method of the optical proximity correction model provided in this embodiment of the invention, the second optical proximity correction model has been verified, indicating that the second optical proximity correction model is reliable. The graphic obtained after correcting the target graphic using the second optical proximity correction model can meet the manufacturing requirements. Thus, after performing iterative correction operations on the target graphic using the first optical proximity correction model, a corrected test graphic is obtained. The first optical proximity correction model can then be verified using the second optical proximity correction model. Since the second optical proximity correction model is reliable, and different photomasks are used in each of the multiple correction stages during the iterative correction operation on the target graphic, this method is effective. The rule constraint value ensures that the spacing between the target pattern after optical proximity correction is within a preset range, thereby reducing the error between different models. Furthermore, since both the second and first optical proximity correction models are built based on the same second layout, the differences between models can be further reduced. This improves the accuracy of the second optical proximity correction model in verifying the first optical proximity correction model and enables cross-validation between different optical proximity correction models. Moreover, it eliminates the need to produce additional test masks and collect data on the actual pattern of the physical wafer after photolithography based on the test masks, thus improving verification efficiency and reducing verification costs.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be described by way of example below with reference to the accompanying drawings.

[0034] See Figure 2 The flowchart shown in this embodiment of the invention illustrates a verification method for an optical proximity correction model, as follows: Figure 2 As shown, the verification method includes the following steps:

[0035] S110, providing a first layout for validating the model, the first layout including the target graphic.

[0036] In this embodiment, the target graphic is used to verify the established optical proximity correction model.

[0037] In this embodiment, the first layout can be a real design layout, and the target graphic is a real design graphic. The first layout includes a pre-defined graphic that needs to be formed in the mask. The first layout can be designed according to the semiconductor process requirements.

[0038] In other embodiments, depending on actual needs, the first layout may also be a test layout with test graphics, or the first layout may also include actual design graphics and test graphics.

[0039] In this embodiment, the first layout may include multiple target graphics, wherein the relative relationship between the multiple target graphics may include one or more of the following: corner-to-corner, edge-to-edge, and corner-to-edge.

[0040] S120 provides a first optical proximity correction model to be verified and a second optical proximity correction model that has been verified.

[0041] In this embodiment, the first optical proximity correction model and the second optical proximity correction model can be obtained based on the same second pattern. The difference is that the second optical proximity correction model has been verified based on the second pattern. That is, the second optical proximity correction model can be obtained by verifying the initial optical proximity correction model based on the actual exposure pattern and the simulated exposure pattern of the second pattern, while the first optical proximity correction model has not been verified.

[0042] S130, the target image is iteratively corrected using the first optical proximity correction model to obtain a corrected test image. The iterative correction operation includes multiple correction stages, each of which uses a different mask rule constraint value, and the mask rule constraint value is greater than or equal to the minimum spacing value of the mask writing.

[0043] In this embodiment, when performing iterative correction operations on the target image using the first optical proximity correction model, the iterative correction operation includes multiple correction stages, and each correction stage uses a different mask rule constraint value. The mask rule constraint value is greater than or equal to the minimum spacing value written by the mask. This can increase the spacing between the test images after optical proximity correction, improve the optical resolution of the images, and ensure that the minimum spacing of the pattern on the mask is large enough to reduce pattern distortion caused by proximity effect. Therefore, the first optical proximity correction model has higher correction accuracy, and this iterative correction method can ensure that the spacing between the target images after optical proximity correction is within a preset range, thereby reducing the error between different models.

[0044] Furthermore, after completing the iterative correction operation, a corrected test image can be obtained, which can serve as the basis for verifying the optical proximity correction model.

[0045] In this embodiment, multiple different photomask rule constraint values ​​all satisfy the condition that they are greater than or equal to the minimum spacing value of the photomask writing.

[0046] The mask rule constraint value is used to limit the conditions that the mask rule check must meet. The mask rule constraint value limits the degree and direction of optical proximity correction in each correction stage. By making different mask rule constraint values ​​used in multiple correction stages, and making the mask rule constraint value greater than or equal to the minimum spacing value of the mask writing, the spacing between the test patterns after optical proximity correction can be increased, improving the optical resolution of the patterns. At the same time, it can ensure that the minimum spacing of the pattern on the mask is sufficient to accurately transfer the pattern to the wafer, thereby reducing pattern distortion caused by proximity effect. Correspondingly, it can improve the correction capability of the second optical proximity correction model for the pattern. Moreover, this iterative correction method can make the spacing between the target patterns after optical proximity correction within a preset range, thereby reducing the error between different models.

[0047] In this embodiment, during the iterative correction operation, the mask rule constraint value used in one correction stage is equal to the minimum spacing value of the mask writing, while the mask rule constraint values ​​used in the other correction stages are greater than the minimum spacing value of the mask writing.

[0048] Specifically, the minimum spacing value of the photomask writing represents the limit of the photomask processing capability. By making the photomask rule constraint value used in one of the correction stages equal to the minimum spacing value of the photomask writing, it is possible to ensure that the minimum spacing of the pattern on the photomask is not less than the minimum spacing value of the photomask writing after correction. This can reduce the image distortion caused by the optical proximity effect, especially the image distortion problem in dense image areas.

[0049] In one specific embodiment, during the iterative correction operation, the mask rule constraint value used in the last correction stage is equal to the minimum spacing value of the mask writing.

[0050] In other words, the mask rule constraint values ​​used in other correction stages are all greater than the minimum spacing value for mask writing. Before executing the last correction stage, the spacing between the patterns after optical proximity correction has been increased, thereby enhancing the optical resolution of the patterns. Thus, when executing the last correction stage, the mask rule constraint values ​​can be reduced, allowing the iterative correction operation to converge. Furthermore, in other correction stages, using more relaxed correction conditions can accelerate the correction of the test patterns by the optical proximity correction model, enabling the optical proximity correction model to converge faster.

[0051] In this embodiment, during the iterative correction operation, according to the execution order of the correction stages, the mask rule constraint values ​​used in each of the other correction stages change in a gradient decreasing manner, or in a gradient increasing manner, or in a manner that first decreases and then increases, or in a manner that first increases and then decreases.

[0052] When performing iterative correction operations, using mask rule constraint values ​​with different changing trends can be applied to correction operations for different target graphics, improving the universality of iterative correction operations. Furthermore, by using mask rule constraint values ​​with changing trends, the number of mask rule constraint values ​​falling into the error range of the first optical proximity correction model can be reduced, enabling the first optical proximity correction model to converge faster.

[0053] In one specific embodiment, if there are many diagonal designs in the actual layout and the pitch between adjacent graphics is small (e.g., 90nm to 140nm), the actual layout can be corrected by iteratively changing the photomask rule constraint values ​​in a gradient-decreasing manner.

[0054] In this embodiment, during the iterative correction operation, in each of the other correction stages, the mask rule constraint value of at least one correction stage is greater than the minimum spacing value between the target graphics, the mask rule constraint value of at least one correction stage is equal to the minimum spacing value between the target graphics, and the mask rule constraint value of at least one correction stage is less than the minimum spacing value between the target graphics.

[0055] In other words, during the iterative correction process, the minimum spacing between test patterns and the minimum spacing of mask writing are considered simultaneously, which enables more precise correction of the target pattern. This allows for accurate control of the size and alignment during the lithography process, thereby increasing the tolerance range of the process.

[0056] Furthermore, by using the minimum spacing values ​​between the target graphics that are greater than, equal to, and less than the mask rule constraint values ​​in the correction stage, the spacing of the corrected test graphics can be increased, so that the corrected test graphics can fall within the coverage of different optical proximity correction models. The correction results of different optical proximity correction models are more accurate, and the edge placement error between different models can be significantly reduced.

[0057] In one specific embodiment, assuming the minimum spacing between target graphics is 'a', then the photomask rule constraint value greater than the minimum spacing between target graphics is any value between 1.05 and 1.1 times the minimum spacing between target graphics, i.e., any value between 1.05a and 1.1a; the photomask rule constraint value less than the minimum spacing between target graphics is any value between 0.9 and 0.95 times the minimum spacing between target graphics, i.e., any value between 0.9a and 0.95a.

[0058] In actual test layouts, it is rare for the spacing between test patterns to be the minimum spacing value 'a'. Therefore, by setting the mask rule constraint value to 1.05 to 1.1 times and 0.9 to 0.95 times the minimum spacing value between target patterns, the optical proximity correction model can better match the actual situation in its correction process for the target patterns, thus improving the accuracy of the correction results.

[0059] Specifically, within different correction processes of a correction phase, only one mask rule constraint value can be used for correction, i.e., one correction phase corresponds to one mask rule constraint value; or different mask rule constraint values ​​from the allowed range can be used for correction, i.e., one correction phase corresponds to multiple different mask rule constraint values.

[0060] It should be noted that the numbers in the above examples are for illustrative purposes only. They are used to indicate that mask rule constraint values ​​smaller than the minimum spacing between target graphics and mask rule constraint values ​​larger than the minimum spacing between target graphics can be used to perform correction operations on the target graphics. They should not be construed as limitations on the present invention.

[0061] In this embodiment, the above-mentioned iterative correction operation is used, and the mask rule constraint values ​​are different in different correction stages.

[0062] Based on this, before performing iterative correction operations on the target image using the first optical proximity correction model, the verification method of the optical proximity correction model further includes: dividing the iterative correction operations into multiple different correction stages based on a preset total number of iterations for performing iterative correction operations on the target image using the first optical proximity correction model; and setting mask rule constraint values ​​for each correction stage.

[0063] Specifically, the preset total number of iterations represents the number of times the first optical proximity correction model corrects the target image. Based on the preset total number of iterations, different division methods can be used to obtain multiple different correction stages. Then, according to the number of correction stages, the mask rule constraint value of the correction stage can be set.

[0064] In one specific embodiment, if the preset total number of iterations is large, a relatively large number of correction stages can be obtained during the division operation. This way, the difference between the various mask rule constraint values ​​can be smaller, thereby reducing the difference between the mask rule constraint values ​​in different correction stages while covering a wide range of mask rule constraint values. This allows for a smoother change in the degree of correction of the target pattern, thereby improving the effect of optical proximity correction.

[0065] In another specific embodiment, if the preset total number of iterations is small, then a relatively small number of correction stages can be obtained when performing the partitioning operation. This can appropriately increase the difference between the constraint values ​​of each mask rule, thereby increasing the range of the constraint values ​​of the mask rule and reducing or avoiding the situation where the constraint values ​​of the mask rule are too concentrated in a certain segment, which would lead to non-convergence.

[0066] It should be noted that the methods for dividing the correction stages and setting the mask rule constraint values ​​listed in the above scheme are only illustrative examples. They are applicable to the division of correction stages and setting of mask rule constraint values ​​for each correction stage based on a preset total number of iterations. They should not be construed as limitations on the present invention. The specific settings can be made according to actual correction requirements.

[0067] In this embodiment, the preset total number of iterations can be between 30 and 50.

[0068] By setting the preset total number of iterations to be greater than or equal to 30, the first optical proximity correction model can perform more thorough corrections on the target image. This reduces the probability that the correction process will stop before the simulated exposure image and the actual exposure image are successfully fitted due to a small number of iterations. By setting the preset total number of iterations to be less than or equal to 50, the correction time can be reduced. This is because if the preset total number of iterations is too large, correction operations may still be required even when the correction result is relatively accurate. By setting an upper limit on the preset total number of iterations, the above situation can be avoided, thus reducing the correction time. It also reduces the probability of overcorrection due to too many corrections.

[0069] It should be noted that the preset total number of iterations in the above examples is merely illustrative and should not be construed as a limitation of the present invention. In actual iterative processes, the preset total number of iterations can be obtained based on experience or determined through extensive data and pre-running operations. The present invention does not impose any limitations on the preset total number of iterations.

[0070] In this embodiment, the number of iterations included in each correction stage is the same. This simplifies the OPC correction process, makes the correction process more standardized, and reduces the time spent determining the start and end times of each correction stage, thereby improving the efficiency of the correction process.

[0071] In some other embodiments, the number of iterations included in each correction stage may be different. The present invention does not impose a specific limit on the number of iterations included in each correction stage, as long as the sum of the number of iterations included in all correction stages is the same as the preset total number of iterations.

[0072] In this embodiment, the step of setting the mask rule constraint value for each correction stage may include: obtaining the minimum spacing value between the target graphics on the test layout and the minimum spacing value for mask writing; setting the mask rule constraint value of one correction stage as the minimum spacing value for mask writing; using the minimum spacing value between the target graphics as a reference value, and setting the mask rule constraint values ​​for the remaining correction stages according to the scaling factor corresponding to the remaining correction stages.

[0073] Specifically, the minimum spacing between target patterns is used to characterize the minimum allowable distance between adjacent test patterns, and the minimum spacing of the photomask writing is used to characterize the photomask processing capability limit. By obtaining the minimum spacing between target patterns and the minimum spacing of the photomask writing, and using them as the basis for setting the photomask rule constraint values, the target patterns can be iteratively corrected using the first optical proximity correction model based on their own parameters. Since the photomask rule constraint values ​​in any correction stage are related to the target patterns themselves, the correction accuracy of the target patterns can be improved, and the actual lithography conditions can be adapted to reduce the proximity effect in the lithography process.

[0074] Meanwhile, by using the minimum spacing between target graphics as the baseline value and setting the mask rule constraint values ​​for each of the other correction stages according to the scaling factor corresponding to each of the other correction stages, the scaling factor can be flexibly adjusted, the range of mask rule constraint values ​​can be widened, and the mask rule constraint values ​​can be more adapted to different correction processes. This also increases the process window, so that test graphics can still be correctly manufactured within a wider parameter range.

[0075] In this embodiment, during the partitioning operation, the iterative correction operation can be divided into four correction stages: the first correction stage, the second correction stage, the third correction stage, and the fourth correction stage. The mask rule constraint values ​​used in these four correction stages exhibit a gradient descent variation; specifically: the mask rule constraint value used in the first correction stage is any value between 1.05a and 1.1a; the mask rule constraint value used in the second correction stage is a; the mask rule constraint value used in the third correction stage is any value between 0.9a and 0.95a; and the mask rule constraint value used in the fourth correction stage is b, where b is the minimum spacing value for mask writing.

[0076] In other words, when performing the correction operation, the constraints are first relaxed to increase the spacing between the target graphics after optical proximity correction, thereby improving the optical resolution of the graphics; then, the constraints are gradually tightened so that the corrected graphics can meet the design requirements.

[0077] By adopting the above technical solution, the target image can be iteratively corrected using the first optical proximity correction model, and the corrected test image can be obtained.

[0078] In practical applications, please refer to [further details]. Figure 2 It also includes: performing step S140, verifying the first optical proximity correction model using the second optical proximity correction model based on the corrected test pattern.

[0079] In other words, the second optical proximity correction model can be used to verify the correction capability of the first optical proximity correction model for the target pattern, so as to determine whether the test pattern corrected by the first optical proximity correction model can be correctly transferred to the wafer, and whether the actual pattern on the wafer can match the test pattern in the test layout.

[0080] In this embodiment of the invention, a second optical proximity correction model that has been verified is used to verify the first optical proximity correction model. This method eliminates the need for additional production of test masks, execution of actual photolithography processes, and collection of data on the actual pattern of the physical wafer after photolithography based on the test mask. This can shorten the verification time and save resources and costs.

[0081] Furthermore, since the second optical proximity correction model has been verified, it indicates that the second optical proximity correction model is reliable. The test pattern after being corrected by the second optical proximity correction model can meet the manufacturing requirements. Therefore, the second optical proximity correction model can be used to verify the first optical proximity correction model.

[0082] In this embodiment, the step of verifying the first optical proximity correction model using the second optical proximity correction model based on the corrected test pattern includes: verifying the first optical proximity correction model by simulating the exposure of the corrected test pattern using the first optical proximity correction model and the second optical proximity correction model.

[0083] In other words, after performing iterative correction operations on the target image using the first optical proximity correction model to obtain the corrected test image, the corrected test image can be simulated by using the second optical proximity correction model and the first optical proximity correction model respectively to obtain the second simulated exposure image corresponding to the second optical proximity correction model and the first simulated exposure image corresponding to the first optical proximity correction model. Then, based on the first simulated exposure image and the second simulated exposure image, the first optical proximity correction model can be verified.

[0084] Furthermore, since the first and second simulated exposure patterns are based on the same corrected test pattern, it helps to reduce other interfering factors. Thus, when comparing the first and second simulated exposure patterns, the problem of inaccurate verification results caused by differences in the test patterns can be reduced.

[0085] See Figure 3 and Figure 5 ,in, Figure 3 This is a flowchart illustrating a verification method for an optical proximity correction model according to an embodiment of the present invention. Figure 5 This is a schematic diagram illustrating the principle of verifying an optical proximity correction model in an embodiment of the present invention, in conjunction with [see also...]. Figure 3 The verification steps include:

[0086] S210, the corrected test pattern is simulated and exposed using the first optical proximity correction model to obtain the first simulated exposure pattern corresponding to the first optical proximity correction model.

[0087] S220, the corrected test pattern is simulated and exposed using the second optical proximity correction model to obtain the second simulated exposure pattern corresponding to the second optical proximity correction model.

[0088] S230, obtain the edge placement error or critical dimension difference between the first simulated exposure pattern and the second simulated exposure pattern.

[0089] In this embodiment, as Figure 5 As shown, the first simulated exposure pattern and the second simulated exposure pattern are placed in the same coordinate system. By measuring the edge information of the first simulated exposure pattern and the edge information of the second simulated exposure pattern, the edge placement error between the two is determined.

[0090] Alternatively, the first and second simulated exposure patterns can be placed in the same coordinate system, and the key dimension difference between them can be determined by measuring the key dimension of the preset area in the first and second simulated exposure patterns.

[0091] In this embodiment, the first simulated exposure pattern and the second simulated exposure pattern have the same exposure conditions. This can reduce the influence of exposure conditions on the differences between the first simulated exposure pattern and the second simulated exposure pattern, which is beneficial to further improve the accuracy of the verification results.

[0092] In this embodiment, the second simulated exposure pattern is obtained by simulating the exposure of the corrected test pattern using the second optical proximity correction model.

[0093] In other words, the first and second simulated exposure patterns are obtained based on the same corrected test pattern. This reduces the problem of inaccurate verification results caused by differences in the test pattern when comparing the first and second simulated exposure patterns.

[0094] S240, determine whether the edge placement error or the critical dimension difference meets the requirements. If yes, it means that the edge placement error or the critical dimension difference meets the requirements, and then proceed to step S250. If no, it means that the edge placement error or the critical dimension difference does not meet the requirements, indicating that the verification cannot be passed.

[0095] S250, complete the verification of the first optical proximity correction model, and take the current first optical proximity correction model as the final optical proximity correction model.

[0096] In this embodiment, by performing iterative correction operations on the target image, the error between the second optical proximity correction model and the first optical proximity correction model can be reduced. Therefore, the second optical proximity correction model can be used to perform the verification process of the first optical proximity correction model.

[0097] In practical applications, the inventors found that since the mask rule constraint values ​​used in each OPC correction operation in the existing scheme are all equal to the minimum spacing value of the mask writing, it is easy to cause errors between different optical proximity correction models. Therefore, it is not conducive to ensuring the credibility of using a second optical proximity correction model that has been verified to verify another optical proximity correction model to be verified.

[0098] For details, see Figure 4 The diagram shown illustrates the principle of verifying an optical proximity correction model after correcting a test pattern using a traditional correction method. Figure 4Subgraphs a and b are shown, where subgraph b is a magnified view of the area within the gray circle in subgraph a. Figure 4 The diagrams illustrate the target image and the corrected test image corresponding to the optical proximity correction model to be verified, the first simulated exposure image corresponding to the optical proximity correction model to be verified, and the second simulated exposure image corresponding to the third optical proximity correction model that has been verified.

[0099] The target image is the image before correction, the corrected test image is the image after correction using the optical proximity correction model to be verified, the first simulated exposure image is the image after simulated exposure using the optical proximity correction model to be verified, and the second simulated exposure image is the image after simulated exposure using the second optical proximity correction model.

[0100] See Figure 4 The first simulated exposure pattern is close to the edge of the target pattern, and the error between them is small. This indicates that after optical proximity correction is performed using the optical proximity correction model to be verified, the optical proximity correction model to be verified can correct the test pattern to meet the design requirements. However, when verified by the second optical proximity correction model, the outline of the second simulated exposure pattern exceeds the target pattern, and the edge placement error between the first and second simulated exposure patterns is large (e.g., 3nm). Therefore, the verification results of the second optical proximity correction model show that the correction capability of the optical proximity correction model to be verified cannot meet the requirements.

[0101] And by Figure 4 It is known that the spacing S1 between the test patterns obtained by the existing optical proximity correction method is small, and there is a problem of pattern distortion due to the proximity effect.

[0102] In this embodiment, see Figure 5 , Figure 5 This is a schematic diagram illustrating the principle of verifying an optical proximity correction model using an embodiment of the present invention. Figure 5 Subgraphs a and b are shown, where subgraph b is a magnified view of the area within the gray circle in subgraph a. Figure 5 The diagrams illustrate the target image and the corrected test image corresponding to the first optical proximity correction model to be verified after adopting the iterative correction method, the first simulated exposure image corresponding to the optical proximity correction model to be verified, and the second simulated exposure image corresponding to the second optical proximity correction model that has been verified.

[0103] The target image is the image before correction, the corrected test image is the image after correction using the optical proximity correction model to be verified, the first simulated exposure image is the image after simulated exposure using the optical proximity correction model to be verified, and the second simulated exposure image is the image after simulated exposure using the second optical proximity correction model.

[0104] Since the iterative correction operation includes multiple correction stages, each stage employs different mask rule constraint values, the error between the first optical proximity correction model and the second optical proximity correction model can be reduced. This reduces the edge placement error of the first and second simulated exposure patterns, for example, by reducing it to 0.5 nm. This demonstrates that the first optical proximity correction model can correct the test pattern to meet the design requirements. Furthermore, the verification results of the second optical proximity correction model also indicate that the first optical proximity correction model can correct the test pattern to meet the design requirements. Therefore, it can be shown that the first optical proximity correction model is reliable and can be used as the final optical proximity correction model in the actual process.

[0105] And in conjunction with see Figure 4 and Figure 5 By employing the iterative correction operation in this embodiment, the spacing S2 between the corrected test patterns can also be increased, for example, Figure 5 S2 is greater than Figure 3 The S1 in the image reduces the optical proximity effect and improves the pattern quality on the physical wafer.

[0106] In this embodiment, if the requirements are not met, step S260 is executed to re-execute the step of providing the first optical proximity correction model, and the first optical proximity correction model is the reconstructed first optical proximity correction model.

[0107] In this embodiment, if the edge placement error or critical dimension difference does not meet the requirements, it means that the obtained first optical proximity correction model cannot correct the test pattern that meets the design requirements. In this case, the first optical proximity correction model can be re-established, and then the re-established first optical proximity correction model can be used to perform the iterative correction and verification operations provided in this embodiment to verify the correction capability of the re-established first optical proximity correction model.

[0108] Therefore, by adopting the verification scheme of the above example, it is possible to determine the correction capability of the first optical proximity correction model to the test pattern, thereby obtaining an optical proximity correction model that meets production requirements.

[0109] This embodiment also provides a verification system for the optical proximity correction model corresponding to the verification method of the optical proximity correction model described above. The following description is based on the accompanying drawings.

[0110] It should be noted that the content of the verification system for the optical proximity correction model described below can be referenced in correspondence with the content of the verification method for the optical proximity correction model described above.

[0111] See Figure 6 The functional block diagram shown in this embodiment of the invention is a verification system for an optical proximity correction model. Figure 6 As shown, the verification system 100 for the optical proximity correction model may include: a graphics providing module 110, used to provide a first layout for verifying the model, the first layout including a target graphic; a model providing module 120, used to provide a first optical proximity correction model to be verified and a second optical proximity correction model that has been verified, wherein the first optical proximity correction model and the second optical proximity correction model are established based on the same second layout; a correction module 130, used to perform iterative correction operations on the target graphic using the first optical proximity correction model to obtain a corrected test graphic, wherein the iterative correction operations include multiple correction stages, the multiple correction stages each using different mask rule constraint values, and the mask rule constraint values ​​are greater than or equal to the minimum spacing value of the mask writing; and a verification module 140, used to verify the first optical proximity correction model based on the corrected test graphic using the second optical proximity correction model.

[0112] The verification system 100 using the optical proximity correction model provided in this embodiment of the invention has verified the second optical proximity correction model provided by the model providing module 120, indicating that the second optical proximity correction model is reliable. The resulting image, after being corrected using the second optical proximity correction model, meets manufacturing requirements. Thus, after the correction module 130 performs iterative correction operations on the target image using the first optical proximity correction model, it obtains the corrected test image. The verification module 140 can then use the second optical proximity correction model to verify the first optical proximity correction model. Since the second optical proximity correction model is reliable, and during the iterative correction operation on the target image... The multiple correction stages employ different mask rule constraint values. This approach ensures that the spacing between the target patterns after optical proximity correction is within a preset range, thereby reducing errors between different models. Furthermore, since both the second and first optical proximity correction models are built based on the same second layout, the differences between models can be further reduced. This improves the accuracy of the second optical proximity correction model in verifying the first optical proximity correction model and enables cross-validation between different optical proximity correction models. Moreover, it eliminates the need to produce additional test masks and collect data on the actual patterns of the physical wafer after photolithography based on the test masks, thus improving verification efficiency and reducing verification costs.

[0113] It is understandable that the above division of modules is only a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, the above modules can be implemented by the processor calling software.

[0114] In this embodiment, the first layout provided by the graphic providing module 110 can be a real design layout, and the target graphic is a real design graphic. The first layout includes a pre-defined graphic that needs to be formed in the mask. The first layout can be designed according to the semiconductor process requirements.

[0115] In other embodiments, depending on actual needs, the first layout may also be a test layout with test graphics, or the first layout may also include actual design graphics and test graphics.

[0116] In this embodiment, the target graphic is used to verify the established optical proximity correction model.

[0117] In this embodiment, the first layout may include multiple target graphics, wherein the relative relationship between the multiple target graphics may include one or more of the following: corner-to-corner, edge-to-edge, and corner-to-edge.

[0118] In this embodiment, the first optical proximity correction model and the second optical proximity correction model provided by the model providing module 120 can be obtained based on the same second pattern. The difference is that the second optical proximity correction model has been verified based on the second pattern. That is, the second optical proximity correction model can be obtained by verifying the initial optical proximity correction model based on the actual exposure pattern and the simulated exposure pattern of the second pattern, while the first optical proximity correction model has not been verified.

[0119] In this embodiment, when the first optical proximity correction model performs iterative correction operations on the target image, the iterative correction operations include multiple correction stages, and each correction stage uses a different mask rule constraint value. The mask rule constraint value is greater than or equal to the minimum spacing value written by the mask. This can increase the spacing between the test images after optical proximity correction, improve the optical resolution of the images, and ensure that the minimum spacing of the pattern on the mask is large enough to reduce pattern distortion caused by proximity effect. Therefore, the first optical proximity correction model has higher correction accuracy, and the iterative correction method can ensure that the spacing between the target images after optical proximity correction is within a preset range, thereby reducing the error between different models.

[0120] Furthermore, after completing the iterative correction operation, a corrected test image can be obtained, which can serve as the basis for verifying the optical proximity correction model.

[0121] In this embodiment, multiple different photomask rule constraint values ​​all satisfy the condition that they are greater than or equal to the minimum spacing value of the photomask writing.

[0122] The mask rule constraint value is used to limit the conditions that the mask rule check must meet. The mask rule constraint value limits the degree and direction of optical proximity correction in each correction stage. By making different mask rule constraint values ​​used in multiple correction stages, and making the mask rule constraint value greater than or equal to the minimum spacing value of the mask writing, the spacing between the test patterns after optical proximity correction can be increased, improving the optical resolution of the patterns. At the same time, it can ensure that the minimum spacing of the pattern on the mask is sufficient to accurately transfer the pattern to the wafer, thereby reducing pattern distortion caused by proximity effect. Correspondingly, it can improve the correction capability of the second optical proximity correction model for the pattern. Moreover, this iterative correction method can make the spacing between the target patterns after optical proximity correction within a preset range, thereby reducing the error between different models.

[0123] In this embodiment, during the iterative correction operation, the mask rule constraint value used in one correction stage is equal to the minimum spacing value of the mask writing, while the mask rule constraint values ​​used in the other correction stages are greater than the minimum spacing value of the mask writing.

[0124] Specifically, the minimum spacing value of the photomask writing represents the limit of the photomask processing capability. By making the photomask rule constraint value used in one of the correction stages equal to the minimum spacing value of the photomask writing, it is possible to ensure that the minimum spacing of the pattern on the photomask is not less than the minimum spacing value of the photomask writing after correction. This can reduce the image distortion caused by the optical proximity effect, especially the image distortion problem in dense image areas.

[0125] In one specific embodiment, during the iterative correction operation, the mask rule constraint value used in the last correction stage is equal to the minimum spacing value of the mask writing.

[0126] In other words, the mask rule constraint values ​​used in other correction stages are all greater than the minimum spacing value for mask writing. Before executing the last correction stage, the spacing between the patterns after optical proximity correction has been increased, thereby enhancing the optical resolution of the patterns. Thus, when executing the last correction stage, the mask rule constraint values ​​can be reduced, allowing the iterative correction operation to converge. Furthermore, in other correction stages, using more relaxed correction conditions can accelerate the correction of the test patterns by the optical proximity correction model, enabling the optical proximity correction model to converge faster.

[0127] In this embodiment, during the iterative correction operation, according to the execution order of the correction stages, the mask rule constraint values ​​used in each of the other correction stages change in a gradient decreasing manner, or in a gradient increasing manner, or in a manner that first decreases and then increases, or in a manner that first increases and then decreases.

[0128] When performing iterative correction operations, using mask rule constraint values ​​with different changing trends can be applied to correction operations for different target graphics, improving the universality of iterative correction operations. Furthermore, by using mask rule constraint values ​​with changing trends, the number of mask rule constraint values ​​falling into the error range of the first optical proximity correction model can be reduced, enabling the first optical proximity correction model to converge faster.

[0129] In one specific embodiment, if there are many diagonal designs in the actual layout and the pitch between adjacent graphics is small (e.g., 90nm to 140nm), the actual layout can be corrected by iteratively changing the photomask rule constraint values ​​in a gradient-decreasing manner.

[0130] In this embodiment, during the iterative correction operation, in each of the other correction stages, the mask rule constraint value of at least one correction stage is greater than the minimum spacing value between the target graphics, the mask rule constraint value of at least one correction stage is equal to the minimum spacing value between the target graphics, and the mask rule constraint value of at least one correction stage is less than the minimum spacing value between the target graphics.

[0131] In other words, during the iterative correction process, the minimum spacing between test patterns and the minimum spacing of mask writing are considered simultaneously, which enables more precise correction of the target pattern. This allows for accurate control of the size and alignment during the lithography process, thereby increasing the tolerance range of the process.

[0132] Furthermore, by using the minimum spacing values ​​between the target graphics that are greater than, equal to, and less than the mask rule constraint values ​​in the correction stage, the spacing of the corrected test graphics can be increased, so that the corrected test graphics can fall within the coverage of different optical proximity correction models. The correction results of different optical proximity correction models are more accurate, and the edge placement error between different models can be significantly reduced.

[0133] In one specific embodiment, assuming the minimum spacing between target graphics is 'a', then the photomask rule constraint value greater than the minimum spacing between target graphics is any value between 1.05 and 1.1 times the minimum spacing between target graphics, i.e., any value between 1.05a and 1.1a; the photomask rule constraint value less than the minimum spacing between target graphics is any value between 0.9 and 0.95 times the minimum spacing between target graphics, i.e., any value between 0.9a and 0.95a.

[0134] In actual test layouts, it is rare for the spacing between test patterns to be the minimum spacing value 'a'. Therefore, by setting the mask rule constraint value to 1.05 to 1.1 times and 0.9 to 0.95 times the minimum spacing value between target patterns, the optical proximity correction model can better match the actual situation in its correction process for the target patterns, thus improving the accuracy of the correction results.

[0135] Specifically, within different correction processes of a correction phase, only one mask rule constraint value can be used for correction, i.e., one correction phase corresponds to one mask rule constraint value; or different mask rule constraint values ​​from the allowed range can be used for correction, i.e., one correction phase corresponds to multiple different mask rule constraint values.

[0136] It should be noted that the numbers in the above examples are for illustrative purposes only and are used to represent the mask rule constraint values ​​that can be smaller than or larger than the minimum spacing value between the test patterns to perform correction operations on the test patterns. They should not be construed as limitations on the present invention.

[0137] In this embodiment, the above-mentioned iterative correction operation is used, and the mask rule constraint values ​​are different in different correction stages.

[0138] Based on this, before the correction module 130 performs iterative correction operations on the target image using the first optical proximity correction model, the correction module 130 may further: divide the iterative correction operations into multiple different correction stages based on a preset total number of iterations of the iterative correction operations on the target image using the first optical proximity correction model; and set mask rule constraint values ​​for each correction stage.

[0139] Specifically, the preset total number of iterations represents the number of times the first optical proximity correction model corrects the target image. Based on the preset total number of iterations, the correction module 130 can adopt different division methods to obtain multiple different correction stages. Then, according to the number of correction stages, the correction module 130 can set the mask rule constraint value of the correction stage.

[0140] In one specific embodiment, if the preset total number of iterations is large, a relatively large number of correction stages can be obtained during the division operation. This way, the difference between the various mask rule constraint values ​​can be smaller, thereby reducing the difference between the mask rule constraint values ​​in different correction stages while covering a wide range of mask rule constraint values. This allows for a smoother change in the degree of correction of the target pattern, thereby improving the effect of optical proximity correction.

[0141] In another specific embodiment, if the preset total number of iterations is small, then a relatively small number of correction stages can be obtained when performing the partitioning operation. This can appropriately increase the difference between the constraint values ​​of each mask rule, thereby increasing the range of the constraint values ​​of the mask rule and reducing or avoiding the situation where the constraint values ​​of the mask rule are too concentrated in a certain segment, which would lead to non-convergence.

[0142] It should be noted that the methods for dividing the correction stages and setting the mask rule constraint values ​​listed in the above scheme are only illustrative examples. They are applicable to the division of correction stages and setting of mask rule constraint values ​​for each correction stage based on a preset total number of iterations. They should not be construed as limitations on the present invention. The specific settings can be made according to actual correction requirements.

[0143] In this embodiment, the preset total number of iterations can be between 30 and 50.

[0144] By setting the preset total number of iterations to be greater than or equal to 30, the first optical proximity correction model can more fully correct the target image. This reduces the probability that the parameter optimization of the first optical proximity correction model will stop before the simulated exposure image and the actual exposure image are successfully fitted due to a small number of iterations, thus helping to ensure the accuracy of the second optical proximity correction model. By setting the preset total number of iterations to be less than or equal to 50, the modeling time can be reduced. This is because if the preset total number of iterations is too large, even if the second optical proximity correction model is already relatively accurate, correction operations are still required. By setting an upper limit on the preset total number of iterations, the above situation can be avoided, thus reducing the modeling time. It also reduces the probability of overcorrection due to too many corrections.

[0145] It should be noted that the preset total number of iterations in the above examples is merely illustrative and should not be construed as a limitation of the present invention. In actual iterative processes, the preset total number of iterations can be obtained based on experience or determined through extensive data and pre-running operations. The present invention does not impose any limitations on the preset total number of iterations.

[0146] In this embodiment, the number of iterations included in each correction stage is the same. This simplifies the OPC correction process, makes the correction process more standardized, and reduces the time spent determining the start and end times of each correction stage, thereby improving the efficiency of the correction process.

[0147] In some other embodiments, the number of iterations included in each correction stage may be different. The present invention does not impose a specific limit on the number of iterations included in each correction stage, as long as the sum of the number of iterations included in all correction stages is the same as the preset total number of iterations.

[0148] In this embodiment, the correction module 130 can obtain the minimum spacing value between the target graphics on the test layout and the minimum spacing value of the photomask writing; set the photomask rule constraint value of one of the correction stages to the minimum spacing value of the photomask writing; use the minimum spacing value between the target graphics as the reference value, and set the photomask rule constraint values ​​of the remaining correction stages according to the scaling factor corresponding to the remaining correction stages, so that each correction stage has different photomask rule constraint values.

[0149] Specifically, the minimum spacing value between target patterns is used to characterize the minimum allowable distance between adjacent test patterns, and the minimum spacing value of the photomask writing is used to characterize the photomask processing capability limit. The correction module 130 obtains the minimum spacing value between target patterns and the minimum spacing value of the photomask writing, and uses the two as the basis for setting the photomask rule constraint value. Thus, it can perform iterative correction operations on the test pattern according to the parameters of the target pattern itself using the first optical proximity correction model. Since the photomask rule constraint value of any correction stage is related to the target pattern itself, it can improve the correction accuracy of the test pattern, adapt to the actual photolithography conditions, and reduce the proximity effect in the photolithography process.

[0150] Meanwhile, by using the minimum spacing between target graphics as the baseline value and setting the mask rule constraint values ​​for each of the other correction stages according to the scaling factor corresponding to each of the other correction stages, the scaling factor can be flexibly adjusted, the range of mask rule constraint values ​​can be widened, and the mask rule constraint values ​​can be more adapted to different correction processes. This also increases the process window, so that test graphics can still be correctly manufactured within a wider parameter range.

[0151] In this embodiment, when performing the partitioning operation, the correction module 130 can divide the iterative correction operation into four correction stages: a first correction stage, a second correction stage, a third correction stage, and a fourth correction stage. The mask rule constraint values ​​used in these four correction stages exhibit a gradient descent variation; that is, the mask rule constraint value used in the first correction stage is any value between 1.05a and 1.1a, the mask rule constraint value used in the second correction stage is a, the mask rule constraint value used in the third correction stage is any value between 0.9a and 0.95a, and the mask rule constraint value used in the fourth correction stage is b, where b is the minimum spacing value for mask writing.

[0152] In other words, when performing the correction operation, the correction module 130 first relaxes the constraints to increase the spacing between the test patterns after optical proximity correction, thereby improving the optical resolution of the patterns; then, it gradually tightens the constraints so that the corrected patterns can meet the design requirements.

[0153] Using the above technical solution, the correction module 130 can perform iterative correction operations on the target image using the first optical proximity correction model, and can obtain the corrected test image.

[0154] In practical applications, after obtaining the corrected test pattern, the verification module 140 can use the second optical proximity correction model to verify the first optical proximity correction model in order to determine whether the test pattern corrected by the first optical proximity correction model can be correctly transferred to the wafer, and whether the actual pattern on the wafer can match the test pattern in the test layout.

[0155] Furthermore, since the second optical proximity correction model has been verified, it indicates that the second optical proximity correction model is reliable. The test pattern after being corrected by the second optical proximity correction model can meet the manufacturing requirements. Therefore, the second optical proximity correction model can be used to verify the first optical proximity correction model.

[0156] In this embodiment, based on the corrected test pattern, the verification module 140 can use the first optical proximity correction model and the second optical proximity correction model to simulate the exposure of the corrected test pattern and verify the first optical proximity correction model.

[0157] In other words, after performing iterative correction operations on the target image using the first optical proximity correction model to obtain the corrected test image, the corrected test image can be simulated by using the second optical proximity correction model and the first optical proximity correction model respectively to obtain the second simulated exposure image corresponding to the second optical proximity correction model and the first simulated exposure image corresponding to the first optical proximity correction model. Then, based on the first simulated exposure image and the second simulated exposure image, the first optical proximity correction model can be verified.

[0158] Furthermore, since the first and second simulated exposure patterns are based on the same corrected test pattern, it helps to reduce other interfering factors. Thus, when comparing the first and second simulated exposure patterns, the problem of inaccurate verification results caused by differences in the test patterns can be reduced.

[0159] In this embodiment, the verification module 140 can use the first optical proximity correction model to simulate exposure of the corrected test pattern to obtain a first simulated exposure pattern corresponding to the first optical proximity correction model, and use the second optical proximity correction model to simulate exposure of the corrected test pattern to obtain a second simulated exposure pattern corresponding to the second optical proximity correction model. Then, the verification module 140 can obtain the edge placement error or critical size difference between the first simulated exposure pattern and the second simulated exposure pattern, wherein the exposure conditions corresponding to the first simulated exposure pattern and the second simulated exposure pattern are the same. Then, the verification module 140 can determine whether the edge placement error or the critical size difference meets the requirements. If so, it indicates that the edge placement error or the critical size difference meets the requirements, and the verification of the first optical proximity correction model is completed, and the current first optical proximity correction model is taken as the final optical proximity correction model.

[0160] If not, it indicates that the edge placement error or the critical dimension difference does not meet the requirements, and the characterization cannot pass the verification. In this case, the step of providing the first optical proximity correction model can be repeated, and the first optical proximity correction model is the reconstructed first optical proximity correction model.

[0161] Then, the re-established first optical proximity correction model is used to perform the iterative correction and verification operations provided in this embodiment to verify the correction capability of the re-established first optical proximity correction model.

[0162] Therefore, by adopting the verification scheme of the above example, it is possible to determine the correction capability of the first optical proximity correction model to the test pattern, thereby obtaining an optical proximity correction model that meets production requirements.

[0163] Accordingly, embodiments of the present invention also provide an electronic device that can implement the verification method of the optical proximity correction model provided in the embodiments of the present invention by loading the above-described verification method of the optical proximity correction model in the form of a program.

[0164] See Figure 7 The diagram illustrates an optional hardware structure of an electronic device according to an embodiment of the present invention. The device in this embodiment includes: at least one processor 01, at least one communication interface 02, at least one memory 03, and at least one communication bus 04.

[0165] In this embodiment, the number of processor 01, communication interface 02, memory 03 and communication bus 04 is at least one, and processor 01, communication interface 02 and memory 03 communicate with each other through communication bus 04.

[0166] Communication interface 02 can be an interface for a communication module used for network communication, such as the interface for a GSM module.

[0167] Processor 01 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the verification method of the optical proximity correction model of this embodiment.

[0168] Memory 03 may include high-speed RAM, and may also include non-volatile memory, such as at least one disk storage device. Memory 03 stores one or more computer instructions, which are executed by processor 01 to implement the verification method of the optical proximity correction model provided in the foregoing embodiments.

[0169] It should be noted that the above-described implementing electronic device may also include other devices (not shown) that may not be essential to understanding the content disclosed in the embodiments of the present invention; given that these other devices may not be essential to understanding the content disclosed in the embodiments of the present invention, the embodiments of the present invention will not describe them one by one.

[0170] Accordingly, embodiments of the present invention also provide a computer program product, including a computer program / instructions, which, when executed by a processor, are used to implement the verification method of the optical proximity correction model described in the embodiments of the present invention.

[0171] This invention also provides a storage medium storing one or more computer instructions for implementing the verification method of the optical proximity correction model provided in the foregoing embodiments.

[0172] The embodiments of the present invention described above are combinations of elements and features of the present invention. Unless otherwise stated, elements or features may be considered optional. Individual elements or features may be practiced without combination with other elements or features. Furthermore, embodiments of the present invention may be constructed by combining some elements and / or features. The order of operations described in the embodiments of the present invention may be rearranged. Some constructions of any embodiment may be included in another embodiment and may be replaced by corresponding constructions of another embodiment. It will be apparent to those skilled in the art that claims in the appended claims that are not explicitly referenced in each other may be combined to form embodiments of the present invention, or may be incorporated as new claims in amendments made after the filing of this application.

[0173] Embodiments of the present invention can be implemented by various means, such as hardware, firmware, software, or combinations thereof. In a hardware configuration, the method according to an exemplary embodiment of the present invention can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0174] In firmware or software configuration, embodiments of the present invention can be implemented in the form of modules, processes, functions, etc. Software code can be stored in a memory unit and executed by a processor. The memory unit is located inside or outside the processor and can send data to and receive data from the processor via various known means.

[0175] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is accorded the widest scope consistent with the principles and novel features disclosed herein.

[0176] While this specification discloses the invention as described above, the invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of this invention should be determined by the scope defined in the claims.

Claims

1. A verification method for an optical proximity correction model, characterized in that, include: A first layout for validating the model is provided, the first layout including the target graphic; A first optical proximity correction model to be verified and a second optical proximity correction model that has been verified are provided, wherein the first optical proximity correction model and the second optical proximity correction model are established based on the same second layout; The target image is corrected by iteratively using the first optical proximity correction model to obtain a corrected test image. The iterative correction operation includes multiple correction stages, each of which uses a different mask rule constraint value. The mask rule constraint value is greater than or equal to the minimum spacing value written by the mask. Based on the corrected test pattern, the first optical proximity correction model is verified using the second optical proximity correction model.

2. The verification method for the optical proximity correction model according to claim 1, characterized in that, One of the correction stages uses a mask rule constraint value equal to the minimum spacing value of the mask being written, while the other correction stages use mask rule constraint values ​​greater than the minimum spacing value of the mask being written.

3. The verification method for the optical proximity correction model according to claim 2, characterized in that, The mask rule constraint value used in the final correction stage is equal to the minimum spacing value of the mask writing.

4. The verification method for the optical proximity correction model according to claim 3, characterized in that, According to the execution order of the aforementioned correction phases, the mask rule constraint values ​​used in the remaining correction phases change in a gradient decreasing manner, or in a gradient increasing manner, or in a manner that first decreases and then increases, or in a manner that first increases and then decreases.

5. The verification method for the optical proximity correction model according to claim 2, characterized in that, In each of the remaining correction stages, the mask rule constraint value of at least one correction stage is greater than the minimum spacing value between the target graphics, the mask rule constraint value of at least one correction stage is equal to the minimum spacing value between the target graphics, and the mask rule constraint value of at least one correction stage is less than the minimum spacing value between the target graphics.

6. The verification method for the optical proximity correction model according to claim 5, characterized in that, The photomask rule constraint value that is greater than the minimum spacing value between the target graphics is any value between 1.05 and 1.1 times the minimum spacing value between the target graphics; The mask rule constraint value, which is less than the minimum spacing value between the target graphics, is any value between 0.9 and 0.95 times the minimum spacing value between the target graphics.

7. The verification method for the optical proximity correction model according to any one of claims 1 to 6, characterized in that, Before performing iterative correction operations on the target image using the first optical proximity correction model, the verification method for the optical proximity correction model further includes: The preset total number of iterations for the iterative correction operation on the target image based on the first optical proximity correction model is used to divide the iterative correction operation into multiple different correction stages. Set the mask rule constraint values ​​for each correction stage.

8. The verification method for the optical proximity correction model according to claim 7, characterized in that, The number of iterations included in each correction phase is the same.

9. The verification method for the optical proximity correction model according to claim 7, characterized in that, The preset total number of iterations is 30 to 50.

10. The verification method for the optical proximity correction model according to claim 7, characterized in that, The steps for setting mask rule constraint values ​​for each correction stage include: Obtain the minimum spacing value between the target graphics on the first layout, and the minimum spacing value for photomask writing; Set the mask rule constraint value of one of the correction stages to the minimum spacing value for mask writing; Using the minimum spacing between the target graphics as the baseline value, and based on the scaling factor corresponding to each of the other correction stages, set the mask rule constraint values ​​for each of the other correction stages.

11. The verification method for the optical proximity correction model according to claim 1, characterized in that, The step of verifying the first optical proximity correction model using the second optical proximity correction model based on the corrected test image includes: The first optical proximity correction model is verified by simulating the exposure of the corrected test pattern using the first optical proximity correction model and the second optical proximity correction model.

12. The verification method for the optical proximity correction model according to claim 11, characterized in that, The step of verifying the first optical proximity correction model by simulating the exposure of the corrected test pattern using the first optical proximity correction model and the second optical proximity correction model includes: The corrected test pattern is simulated by using the first optical proximity correction model to obtain the first simulated exposure pattern corresponding to the first optical proximity correction model. The corrected test pattern is simulated by using the second optical proximity correction model to obtain the second simulated exposure pattern corresponding to the second optical proximity correction model. Obtain the edge placement error or critical dimension difference between the first simulated exposure graphic and the second simulated exposure graphic, where the exposure conditions corresponding to the first simulated exposure graphic and the second simulated exposure graphic are the same; Determine whether the edge placement error or the critical dimension difference meets the requirements; If the edge placement error or the critical dimension difference meets the requirements, the first optical proximity correction model is verified, and the current first optical proximity correction model is used as the final optical proximity correction model. Otherwise, the representation cannot be verified.

13. The verification method for the optical proximity correction model according to claim 12, characterized in that, Also includes: If the edge placement error or the critical dimension difference does not meet the requirements, the step of providing the first optical proximity correction model is repeated, and the first optical proximity correction model is the reconstructed first optical proximity correction model.

14. A verification system for an optical proximity correction model, characterized in that, include: A graphics providing module is used to provide a first layout for validating the model, the first layout including the target graphics; The model providing module is used to provide a first optical proximity correction model to be verified and a second optical proximity correction model that has been verified, wherein the first optical proximity correction model and the second optical proximity correction model are established based on the same second layout; The correction module is used to perform iterative correction operations on the target image using the first optical proximity correction model to obtain a corrected test image. The iterative correction operation includes multiple correction stages, each of which uses a different mask rule constraint value, and the mask rule constraint value is greater than or equal to the minimum spacing value written by the mask. The verification module is used to verify the first optical proximity correction model based on the corrected test pattern using the second optical proximity correction model.

15. An electronic device, characterized in that, include: At least one memory and at least one processor, the memory storing one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the verification method of the optical proximity correction model as described in any one of claims 1 to 13.

16. A storage medium, characterized in that, The storage medium stores one or more computer instructions for implementing the verification method of the optical proximity correction model as described in any one of claims 1 to 13.

17. A computer program product, characterized in that, Includes computer instructions, which, when executed by a processor, are used to implement the verification method for the optical proximity correction model as described in any one of claims 1 to 13.

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