Lithography machine matching method

Abstract

The present application relates to the technical field of photoetching machine, especially to a photoetching machine matching method, comprising the steps of: obtaining preset photoetching patterns, each of which is provided with X key positions, X being a positive integer; obtaining the target key size corresponding to the X key positions of each preset photoetching pattern on a target photoetching machine according to a photoetching OPC model; fitting the OPC model of a to-be-adjusted photoetching machine with the target photoetching machine as a standard to obtain the to-be-adjusted key size corresponding to the X key positions in each preset photoetching pattern on the to-be-adjusted photoetching machine, and calculate the difference between the to-be-adjusted key size and the target key size; establishing a sensitivity matrix based on the sensitivity of each to-be-adjusted key size to each adjustable parameter of the photoetching machine; establishing a total evaluation function according to the sensitivity matrix; and adjusting the parameters of the to-be-adjusted photoetching machine according to the total evaluation function to adjust the matching between the to-be-measured key size and the target key size.

Description

Technical Field

[0001] This invention relates to the field of lithography machine technology, and in particular to a lithography machine matching method. Background Technology

[0002] Optical lithography involves modeling light using optical and chemical models and mathematical formulas. Light is irradiated through a mask, causing diffraction and converging on the photoresist surface. The projected light then excites chemical reactions on the photoresist, and baking makes the photoresist locally soluble in the developer. Simulating the reactions occurring on the photoresist and exploring ways to increase lithographic resolution and process window through calculations is called photolithography OPC modeling.

[0003] In mass production, multiple lithography machines used on the same production line may come from different suppliers. The lithography process for chips may vary in function and performance between different lithography machines. In other words, different models of lithography machines may result in different performance variations for the same lithography process, which may lead to decreased mass production efficiency and a decrease in yield due to performance degradation. Summary of the Invention

[0004] To address the issue of performance differences among multiple lithography machines used in the same production line, this invention provides a lithography machine matching method.

[0005] The solution to the technical problem of this invention is to provide a lithography machine matching method for matching multiple lithography machines on the same production line, comprising the following steps:

[0006] Obtain preset lithography patterns. Each preset lithography pattern has N preset key positions, where N is a positive integer.

[0007] On the target lithography machine, based on the lithography OPC model, obtain the target key dimensions corresponding to the N key positions of each preset lithography pattern;

[0008] Using the target lithography machine as a standard, an OPC model is fitted to the lithography machine to be adjusted to obtain the key dimensions to be adjusted corresponding to N key positions in each preset lithography pattern on the lithography machine to be adjusted, and the difference between the key dimensions to be adjusted and the target key dimensions is calculated.

[0009] A sensitivity matrix is ​​established based on the sensitivity of each lithography machine adjustable parameter to each key dimension to be adjusted;

[0010] Based on the sensitivity matrix, establish the overall evaluation function;

[0011] Based on the overall evaluation function, the parameters of the lithography machine to be tuned are adjusted to match the critical dimension to be measured with the target critical dimension.

[0012] Preferably, the acquisition of the preset photolithography pattern, wherein each preset photolithography pattern has N preset key positions, specifically includes the following steps:

[0013] The design selects a preset lithographic pattern, which includes a one-dimensional lithographic pattern and / or a two-dimensional lithographic pattern.

[0014] The key positions of each preset photolithography pattern are marked and denoted as Gj, j=1,2,…N.

[0015] Preferably, the target key dimensions corresponding to N key positions of each preset lithography pattern are obtained on the target lithography machine according to the lithography OPC model, specifically including the following steps:

[0016] The lithography parameters are adjusted sequentially for each preset lithography pattern on the target lithography machine, and the corresponding OPC model is generated.

[0017] Each preset lithography pattern is simulated, exposed on a lithography machine, and SEM images of the lithography pattern are obtained.

[0018] Extract the contour of each SEM image, and extract X target key dimensions CD at key locations in the contour, denoted as Sij, i=1,2,…M, j=1,2,…N, where M is the number of preset lithographic patterns.

[0019] Preferably, the step of generating a lithography OPC model matching the target lithography machine based on the lithography OPC model of the target lithography machine on the lithography machine to be adjusted, and obtaining the key dimensions to be adjusted corresponding to N key positions in each preset lithography pattern on the lithography machine to be adjusted, specifically includes the following steps:

[0020] Based on the parameters of the target lithography machine, the parameters of the lithography machine to be tuned are adjusted so that the lithography OPC model of the lithography machine to be tuned matches the lithography OPC model of the target lithography machine.

[0021] The lithography machine to be adjusted is simulated to obtain the corresponding simulation model, and the key dimensions to be adjusted corresponding to the key positions in the preset lithography pattern are obtained from the simulation model.

[0022] Preferably, the sensitivity matrix of the lithography machine to be tuned is obtained by perturbing the input parameters of the lithography machine to be tuned.

[0023] Preferably, the process of perturbing the input parameters of the lithography machine to be tuned to obtain the sensitivity matrix specifically includes the following steps:

[0024] Adjust any adjustable parameter P of the lithography machine to be tuned. Using the target critical dimension of the critical position obtained by the target lithography machine as the standard, model and calculate the target critical dimension of the critical position. Let the target critical dimension at the j-th critical position be Gj, and let CDj be the critical dimension. The sensitivity of CDj to the adjustable parameter P is: Corresponding to the parameters before matching, Let P be the infinitesimal change in P;

[0025] By combining multiple adjustable parameters P1, P2...PN, the sensitivity matrix is ​​obtained.

[0026]

[0027] N is a positive integer.

[0028] Preferably, establishing the overall evaluation function based on the sensitivity matrix specifically includes the following steps:

[0029] Based on the sensitivity matrix, different parameters are adjusted to obtain the changes in the key dimension to be adjusted under small adjustments of different parameters. These changes are then summed to obtain the cost value of each key dimension to be adjusted; cost is the adjusted error, which is the change in the key dimension to be adjusted; the formula for cost is: ;

[0030] The overall evaluation function is obtained by combining the evaluation functions of each parameter; the formula is: .

[0031] Preferably, the lithography machine matching method further includes the following steps:

[0032] Based on the overall evaluation function, the parameters of the lithography machine to be tuned are adjusted and the preset lithography pattern is simulated. The key dimensions to be measured are obtained from the simulation model, and it is determined whether the obtained key dimensions to be measured match the obtained target key dimensions.

[0033] If a match is found, the adjustment of the lithography machine to be adjusted is terminated.

[0034] If there is a mismatch, the overall evaluation function is further optimized through image error to obtain an optimized evaluation function, and the lithography machine to be tuned is adjusted through the optimized evaluation function.

[0035] Preferably, the process involves adjusting the parameters of the lithography machine to be tuned based on the overall evaluation function and simulating a preset lithography pattern. The key dimensions to be measured are obtained from the simulation model, and it is determined whether the obtained key dimensions match the target key dimensions. If they match, the adjustment of the lithography machine to be tuned ends. If they do not match, the overall evaluation function is further optimized using image errors to obtain an optimized evaluation function. The lithography machine to be tuned is then adjusted using the optimized evaluation function. This process specifically includes the following steps:

[0036] The preset lithography pattern is simulated by adjusting the lithography machine to be tuned;

[0037] The absolute value of the difference between the value of the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine is compared with a preset threshold.

[0038] If the absolute value of the difference between the value of the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine is less than or equal to the threshold, then it is determined that the lithography machine to be adjusted and the target lithography machine are matched.

[0039] If the absolute value of the difference between the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the target key dimension in the image obtained by the target lithography machine is greater than the threshold, then the two images are judged to be mismatched, and further optimization is needed to obtain the optimization evaluation function.

[0040] Preferably, the further optimization involves introducing a penalty function into the overall evaluation function to obtain an optimized evaluation function. The penalty function is obtained by pre-setting additional key positions on each preset lithography pattern and constructing a sensitivity matrix. The optimized evaluation function obtained after introducing the penalty function is as follows: Where λ is the penalty factor, used to regulate... exist The proportion in.

[0041] Compared with the prior art, the lithography machine matching method of the present invention has the following advantages:

[0042] 1. The lithography machine matching method of the present invention includes the following steps:

[0043] A preset lithography pattern is obtained, with N key positions (N being a positive integer) in each pattern. On the target lithography machine, the target key dimensions corresponding to the N key positions of each preset lithography pattern are obtained according to the lithography OPC model. Using the target lithography machine as a standard, the OPC model is fitted to the lithography machine to be adjusted, obtaining the key dimensions to be adjusted corresponding to the N key positions in each preset lithography pattern on the machine to be adjusted, and calculating the difference between the key dimensions to be adjusted and the target key dimensions. A sensitivity matrix is ​​established based on the sensitivity of each adjustable parameter of the lithography machine to each key dimension to be adjusted. Based on the sensitivity matrix, a total evaluation function is established. Based on the total evaluation function, the parameters of the lithography machine to be adjusted are adjusted to match the key dimensions to be measured with the target key dimensions. By perturbing the input parameters to obtain the sensitivity matrix, the calculation of the sensitivity matrix is ​​used as the evaluation function during lithography machine matching. This allows for quick and comprehensive acquisition of the matching parameters of the lithography machine to be adjusted, thereby obtaining a lithography machine with performance comparable to the target lithography machine and solving the matching problem of multiple lithography machines on the same production line.

[0044] 2. In this invention, the preset lithography patterns selected include one-dimensional lithography patterns and / or two-dimensional lithography patterns. The diversity of samples helps to enhance the reliability of the matching results of the lithography machine matching method. Furthermore, by marking the key positions of each preset lithography pattern in advance, it can facilitate subsequent calculations.

[0045] 3. In this invention, the lithography parameters are adjusted sequentially for each preset lithography pattern on the target lithography machine, and a corresponding OPC model is generated; sufficient sample data is used to ensure the reliability of the final result; and the contour of the SEM image is used for comparison to improve the accuracy and comprehensiveness of the comparison.

[0046] 4. In this invention, a lithography OPC model matching the target lithography machine is generated on the lithography machine to be adjusted based on the lithography OPC model of the target lithography machine; the key dimensions to be adjusted corresponding to key positions in the preset lithography pattern are obtained through the lithography machine to be adjusted. By comparing the differences between the two lithography machines, some initial adjustable data can be clarified, preparing for the subsequent establishment of the sensitivity matrix.

[0047] 5. In this invention, the sensitivity matrix of the lithography machine to be tuned is obtained by perturbing the input parameters of the lithography machine to be tuned; in this way, all the data used to establish the sensitivity matrix can be obtained simply.

[0048] 6. In the sensitivity formula of this invention, the rate of change of the adjustable parameter P is small, which facilitates precise control over the changes in the key dimensions to be adjusted at critical positions. By combining multiple adjustable parameters P1, P2...PN to obtain the sensitivity matrix, the matching between the target lithography machine and the lithography machine to be adjusted can be more comprehensive.

[0049] 7. This invention adjusts different parameters based on the sensitivity matrix to obtain the change in the key dimension to be adjusted under small adjustments of different parameters, and then sums these changes to obtain the cost value of each key dimension to be adjusted; cost is the adjusted error, which is the change in the key dimension to be adjusted; the formula for cost is: Then, by combining the evaluation functions of each adjustable parameter, the overall evaluation function is obtained; the formula is: Using the overall evaluation function to adjust the lithography machine helps improve the matching degree between the target lithography machine and the lithography machine to be adjusted.

[0050] 8. In this invention, the matching results will be further verified. If there is no match, the overall evaluation function will be further optimized through image error to obtain an optimized evaluation function. The optimized evaluation function will be used to adjust the lithography machine to be adjusted, which helps to ensure the reliability of the final matching result of the lithography machine to be adjusted.

[0051] 9. In this invention, the degree of matching between the lithography machine to be adjusted and the target lithography machine is determined by the degree of matching between the simulation data and the image data. The absolute value of the difference between the value of the key dimension to be adjusted in the simulation data obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine can intuitively and accurately reflect the degree of matching of the images; and it can effectively reduce the amount of computation.

[0052] 10. In this invention, by introducing additional key point groups for assistance, the evaluation function is further optimized, ensuring the reliability of the final lithography machine matching result; a penalty function is introduced to regulate... exist The proportion in the model helps to further improve the accuracy of the calculation results of the performance difference between the lithography machine under test and the target lithography machine in this lithography machine matching method. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a flowchart of the lithography machine matching method provided in the first embodiment of the present invention.

[0055] Figure 2 This is a flowchart of S1 of the lithography machine matching method provided in the first embodiment of the present invention.

[0056] Figure 3 This is a flowchart of S2 of the lithography machine matching method provided in the first embodiment of the present invention.

[0057] Figure 4 This is a flowchart of S3 of the lithography machine matching method provided in the first embodiment of the present invention.

[0058] Figure 5 This is a flowchart of S4 of the lithography machine matching method provided in the first embodiment of the present invention.

[0059] Figure 6 This is a flowchart of S5 of the lithography machine matching method provided in the first embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0061] The terms “vertical,” “horizontal,” “left,” “right,” “up,” “down,” “upper left,” “upper right,” “lower left,” “lower right,” “lower left,” “lower right,” and similar expressions used in this article are for illustrative purposes only.

[0062] Please see Figure 1 The first embodiment of the present invention provides a lithography machine matching method for matching multiple lithography machines on the same production line, comprising the following steps:

[0063] Step S1: Obtain a preset photolithography pattern. Each preset photolithography pattern has N preset key positions, where N is a positive integer.

[0064] Step S2: On the target lithography machine, obtain the target key dimensions corresponding to the N key positions of each preset lithography pattern according to the lithography OPC model;

[0065] Step S3: Using the target lithography machine as a standard, perform OPC model fitting on the lithography machine to be adjusted, obtain the key dimensions to be adjusted corresponding to N key positions in each preset lithography pattern on the lithography machine to be adjusted, and calculate the difference between the key dimensions to be adjusted and the target key dimensions.

[0066] Step S4: Establish a sensitivity matrix based on the sensitivity of each lithography machine adjustable parameter for each key dimension to be adjusted;

[0067] Step S5: Establish the overall evaluation function based on the sensitivity matrix;

[0068] Step S6: Adjust the parameters of the lithography machine to be tuned according to the overall evaluation function to match the critical dimension to be measured with the target critical dimension;

[0069] Understandably, the lithography machine matching method in this embodiment obtains the sensitivity matrix by perturbing the input parameters. When performing lithography machine matching, the calculation of the sensitivity matrix is ​​used as the evaluation function, which can quickly and comprehensively obtain the matching parameters of the lithography machine to be adjusted, thereby obtaining a lithography machine to be adjusted with performance comparable to the target lithography machine, and solving the matching problem of multiple lithography machines on the same production line.

[0070] It should be noted that the numbering of each step is not strictly limited to their order.

[0071] Please combine Figure 1 and Figure 2 Step S1 specifically includes the following steps:

[0072] Step S11: Design and select a preset photolithography pattern, which includes a one-dimensional photolithography pattern and / or a two-dimensional photolithography pattern.

[0073] Understandably, the diversity of lithographic patterns helps to enhance the reliability of the matching results of the matching method of this lithography machine; and by marking the key positions of each preset lithographic pattern in advance, it can facilitate subsequent calculations.

[0074] Step S12: Mark the key positions of each preset photolithography pattern and denote the key positions in the preset photolithography pattern as Gj, j=1,2,...N, M is the number of preset photolithography patterns.

[0075] Please combine Figure 1 and Figure 3 Step S2 specifically includes the following steps:

[0076] Step S21: Sequentially adjust the lithography parameters for each preset lithography pattern on the target lithography machine and generate the corresponding OPC model.

[0077] Further adjustments to the lithography parameters include setting the illumination mode of the lithography machine, the numerical aperture of the projection lens, the pupil distribution of the illumination system, the exposure dose, the defocus rate, the mechanical vibration of the lithography machine's optical system, the wavelength of the lithography machine, and other adjustable parameters on the lithography machine.

[0078] Step S22: Simulate each preset lithography pattern, expose it on the lithography machine, and obtain the SEM image of the lithography pattern; the SEM image is a scanning electron microscope image.

[0079] Step S23: Extract the contour of each SEM image, and extract X key dimensions to be adjusted for the target key position in the contour, denoted as Sij, i=1,2,…M, j=1,2,…N.

[0080] Understandably, in the lithography machine matching method of this embodiment, the lithography parameters are adjusted sequentially on the target lithography machine for each preset lithography pattern, and a corresponding OPC model is generated; sufficient sample data is used to ensure the reliability of the final result.

[0081] Please combine Figure 1 and Figure 4 Step S3 specifically includes the following steps:

[0082] Step S31: Adjust the parameters of the lithography machine to be adjusted according to the parameters of the target lithography machine so that the lithography OPC model of the lithography machine to be adjusted matches the lithography OPC model of the target lithography machine.

[0083] Specifically, the adjustable parameters of the lithography machine to be tuned, such as the illumination mode, numerical aperture of the projection lens, pupil distribution of the illumination system, exposure dose, defocus rate, mechanical vibration of the optical system, and wavelength, are adjusted to be consistent with the target lithography machine.

[0084] Step S32: Simulate the lithography machine to be adjusted to obtain the corresponding simulation model, and obtain the key dimensions to be adjusted corresponding to the key positions in the preset lithography pattern from the simulation model.

[0085] Understandably, by comparing the differences between the two lithography machines, some initial adjustable data can be identified, which will prepare for the establishment of the subsequent sensitivity matrix.

[0086] Please combine Figure 1 and Figure 5 Step S4 specifically includes the following steps:

[0087] Step S41: Calculate the sensitivity of the target critical dimension at the critical location to a single parameter;

[0088] Specifically, this involves adjusting any adjustable parameter P of the lithography machine to be tuned, using the target key dimension at the critical position obtained by the target lithography machine as the standard, modeling and calculating the target key dimension at the critical position, and denoting the key dimension to be tuned at the j-th critical position Gj as CDj. The sensitivity of CDj to the adjustable parameter P is: Corresponding to the parameters before matching, Let P be the infinitesimal change in P;

[0089] Understandably, a tiny change in P, δP, is achieved by adjusting the corresponding parameters of the lithography machine to be tuned. For example, when the adjustable parameter P is the numerical aperture of the lithography machine's projection lens, a tiny change in P can be achieved by making only a tiny adjustment to the numerical aperture of the lithography machine's projection lens.

[0090] Step S42: Combine multiple adjustable parameters P1, P2...PN to obtain the sensitivity matrix.

[0091]

[0092] N is a positive integer.

[0093] Understandably, the adjustable parameter PN before matching can be represented as PN0.

[0094] In other words, step S4 involves adjusting a single parameter of the lithography machine to be tuned to obtain the sensitivity of the key dimension to be tuned at each key position to that parameter; and then establishing a sensitivity matrix by obtaining the sensitivity of the key dimension to be tuned at each key position to each parameter.

[0095] Furthermore, δP, as a small change in P, is obtained by fine-tuning the corresponding parameters in the lithography machine under test. When fine-tuning the corresponding parameters, the difference between the key dimension to be adjusted and the target key dimension is used as a benchmark to gradually reduce the error between the lithography machine under test and the target lithography machine.

[0096] Furthermore, please combine Figure 1 and Figure 6 The sensitivity matrix of the lithography machine to be tuned is obtained by perturbing the input parameters of the lithography machine. It is understood that in this embodiment, the sensitivity matrix of the lithography machine to be tuned is obtained by perturbing the input parameters of the lithography machine; this method allows for the simple acquisition of all the data used to establish the sensitivity matrix.

[0097] Please combine Figure 1 and Figure 6 Step S5 specifically includes the following steps:

[0098] Step S51: Establish the evaluation function for each adjustable parameter;

[0099] Specifically, based on the sensitivity matrix, different parameters are adjusted to obtain the changes in the key dimension to be adjusted under small adjustments of different parameters. These changes are then summed to obtain the cost value for each key dimension to be adjusted. The cost is the adjusted error, which is the change in the key dimension to be adjusted. The formula for cost is: .

[0100] Understandably, based on the sensitivity matrix, different parameters of the lithography machine to be adjusted can be obtained to get the change of the key dimension to be adjusted under small adjustments of different parameters. By superimposing these changes (i.e. errors), the cost value of the j-th key dimension to be adjusted can be obtained.

[0101] Step S52: Combine the evaluation functions of each adjustable parameter to obtain the overall evaluation function; the formula for the overall evaluation function is: .

[0102] Furthermore, this lithography machine matching method also includes the following steps:

[0103] Step S7: Based on the overall evaluation function, adjust the parameters of the lithography machine to be tuned and simulate the preset lithography pattern. Obtain the key dimension to be measured from the simulation model and determine whether the obtained key dimension to be measured matches the obtained target key dimension.

[0104] If a match is found, the adjustment of the lithography machine to be adjusted is terminated.

[0105] If there is a mismatch, the overall evaluation function is further optimized through image error to obtain an optimized evaluation function, and the lithography machine to be tuned is adjusted through the optimized evaluation function.

[0106] Furthermore, step S7 specifically includes the following steps:

[0107] Step S71: Simulate the preset lithography pattern using the adjusted lithography machine;

[0108] Step S72: Compare the absolute value of the difference between the value of the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine with a preset threshold.

[0109] If the absolute value of the difference between the value of the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine is less than or equal to the threshold, then it is determined that the lithography machine to be adjusted and the target lithography machine are matched.

[0110] If the absolute value of the difference between the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the target key dimension in the image obtained by the target lithography machine is greater than the threshold, then the two images are judged to be mismatched, and further optimization is needed to obtain the optimization evaluation function.

[0111] It should be noted that in this embodiment, the lithography machine to be adjusted acquires data from the simulation model, and the image of the lithography pattern acquired by the target lithography machine is used for comparison, and this image is a SEM image.

[0112] Understandably, in this embodiment, the degree of matching between the lithography machine to be adjusted and the target lithography machine is determined by the degree of matching between the data in the simulation model and the data in the SEM image. This ensures that the degree of matching of the SEM image can be reflected intuitively and accurately, while also effectively reducing the amount of computation.

[0113] Furthermore, a penalty function is introduced into the overall evaluation function to obtain an optimized evaluation function. The penalty function is obtained by presetting additional key positions on each preset lithography pattern and constructing a sensitivity matrix.

[0114] Understandably, introducing another set of key points can help optimize the evaluation function and ensure the reliability of the final lithography machine matching result.

[0115] Specifically, in this embodiment, the threshold is zero. When the absolute value of the difference between the value of the key dimension to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine is greater than zero, a penalty function is introduced.

[0116] Furthermore, the data used to establish the penalty function is obtained from the SEM image acquired through the lithography machine to be tuned.

[0117] Understandably, incorporating the calculation error of SEM image contour extraction into the function can improve the matching accuracy of lithography matching technology at non-critical measurement locations, thereby obtaining optical parameters of the lithography machine to be tuned that are comparable to the performance of the target lithography machine.

[0118] Furthermore, the optimized evaluation function obtained after introducing the penalty function is as follows: Understandable. This is the penalty function; where λ is the penalty factor, used to regulate... exist The proportion in.

[0119] Understandably, this design helps to further improve the accuracy of the calculation results of the performance difference between the lithography machine under test and the target lithography machine in this lithography machine matching method.

[0120] Compared with the prior art, the lithography machine matching method of the present invention has the following advantages:

[0121] 1. The lithography machine matching method of the present invention includes the following steps:

[0122] A preset lithography pattern is obtained, with N key positions (N being a positive integer) in each pattern. On the target lithography machine, the target key dimensions corresponding to the N key positions of each preset lithography pattern are obtained according to the lithography OPC model. Using the target lithography machine as a standard, the OPC model is fitted to the lithography machine to be adjusted, obtaining the key dimensions to be adjusted corresponding to the N key positions in each preset lithography pattern on the machine to be adjusted, and calculating the difference between the key dimensions to be adjusted and the target key dimensions. A sensitivity matrix is ​​established based on the sensitivity of each adjustable parameter of the lithography machine to each key dimension to be adjusted. Based on the sensitivity matrix, a total evaluation function is established. Based on the total evaluation function, the parameters of the lithography machine to be adjusted are adjusted to match the key dimensions to be measured with the target key dimensions. By perturbing the input parameters to obtain the sensitivity matrix, the calculation of the sensitivity matrix is ​​used as the evaluation function during lithography machine matching. This allows for quick and comprehensive acquisition of the matching parameters of the lithography machine to be adjusted, thereby obtaining a lithography machine with performance comparable to the target lithography machine and solving the matching problem of multiple lithography machines on the same production line.

[0123] 2. In this invention, the preset lithography patterns selected include one-dimensional lithography patterns and / or two-dimensional lithography patterns. The diversity of samples helps to enhance the reliability of the matching results of the lithography machine matching method. Furthermore, by marking the key positions of each preset lithography pattern in advance, it can facilitate subsequent calculations.

[0124] 3. In this invention, the lithography parameters are adjusted sequentially for each preset lithography pattern on the target lithography machine, and a corresponding OPC model is generated; sufficient sample data is used to ensure the reliability of the final result; and the contour of the SEM image is used for comparison to improve the accuracy and comprehensiveness of the comparison.

[0125] 4. In this invention, a lithography OPC model matching the target lithography machine is generated on the lithography machine to be adjusted based on the lithography OPC model of the target lithography machine; the key dimensions to be adjusted corresponding to key positions in the preset lithography pattern are obtained through the lithography machine to be adjusted. By comparing the differences between the two lithography machines, some initial adjustable data can be clarified, preparing for the subsequent establishment of the sensitivity matrix.

[0126] 5. In this invention, the sensitivity matrix of the lithography machine to be tuned is obtained by perturbing the input parameters of the lithography machine to be tuned; in this way, all the data used to establish the sensitivity matrix can be obtained simply.

[0127] 6. In the sensitivity formula of this invention, the rate of change of the adjustable parameter P is small, which facilitates precise control over the changes in the key dimensions to be adjusted at critical positions. By combining multiple adjustable parameters P1, P2...PN to obtain the sensitivity matrix, the matching between the target lithography machine and the lithography machine to be adjusted can be more comprehensive.

[0128] 7. This invention adjusts different parameters based on the sensitivity matrix to obtain the change in the key dimension to be adjusted under small adjustments of different parameters, and then sums these changes to obtain the cost value of each key dimension to be adjusted; cost is the adjusted error, which is the change in the key dimension to be adjusted; the formula for cost is: Then, by combining the evaluation functions of each adjustable parameter, the overall evaluation function is obtained; the formula is: Using the overall evaluation function to adjust the lithography machine helps improve the matching degree between the target lithography machine and the lithography machine to be adjusted.

[0129] 8. In this invention, the matching results will be further verified. If there is no match, the overall evaluation function will be further optimized through image error to obtain an optimized evaluation function. The optimized evaluation function will be used to adjust the lithography machine to be adjusted, which helps to ensure the reliability of the final matching result of the lithography machine to be adjusted.

[0130] 9. In this invention, the degree of matching between the lithography machine to be adjusted and the target lithography machine is determined by the degree of matching between the simulation data and the image data. The absolute value of the difference between the value of the key dimension to be adjusted in the simulation data obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine can intuitively and accurately reflect the degree of matching of the images; and it can effectively reduce the amount of computation.

[0131] 10. In this invention, by introducing another set of key points for assistance, it is beneficial to further optimize the evaluation function and ensure the reliability of the final lithography machine matching result; by introducing a penalty function to adjust the proportion of cost_sem(Pi) in cost_sum, it is beneficial to further improve the accuracy of the calculation results of the performance difference between the lithography machine to be adjusted and the target lithography machine in this lithography machine matching method.

[0132] The above provides a detailed description of a lithography machine matching method disclosed in the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention. Any modifications, equivalent substitutions, and improvements made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithography machine matching method for matching multiple lithography machines on the same production line, characterized in that, Includes the following steps: Obtain preset lithography patterns. Each preset lithography pattern has N preset key positions, where N is a positive integer. On the target lithography machine, the target key dimensions corresponding to N key positions of each preset lithography pattern are obtained according to the lithography OPC model. The target key dimensions are extracted from the SEM image obtained by exposing the lithography pattern on the target lithography machine. Using the target lithography machine as a standard, an OPC model is fitted to the lithography machine to be adjusted to obtain the key dimensions to be adjusted corresponding to N key positions in each preset lithography pattern on the lithography machine to be adjusted, and the difference between the key dimensions to be adjusted and the target key dimensions is calculated. A sensitivity matrix is ​​established based on the sensitivity of each lithography machine adjustable parameter to each key dimension to be adjusted; Based on the sensitivity matrix, establish the overall evaluation function; Based on the overall evaluation function, adjust the parameters of the lithography machine to be tuned to match the critical dimension to be measured with the target critical dimension; The step of adjusting the parameters of the lithography machine to be tuned according to the overall evaluation function to match the critical dimension to be measured with the target critical dimension includes: Based on the overall evaluation function, the parameters of the lithography machine to be tuned are adjusted and the preset lithography pattern is simulated. The key dimensions to be measured are obtained from the simulation model, and it is determined whether the obtained key dimensions to be measured match the obtained target key dimensions. If a match is found, the adjustment of the lithography machine to be adjusted is terminated. If there is a mismatch, the overall evaluation function is further optimized using image errors to obtain an optimized evaluation function, which is then used to adjust the lithography machine to be tuned; where... The step of further optimizing the overall evaluation function through image errors to obtain the optimized evaluation function includes: A penalty function is introduced into the overall evaluation function to obtain the optimized evaluation function. The penalty function is obtained by introducing another set of key points on each preset lithography pattern and constructing a sensitivity matrix.

2. The lithography machine matching method as described in claim 1, characterized in that, The process of obtaining a preset photolithography pattern, wherein each preset photolithography pattern has N preset key positions, specifically includes the following steps: The design selects a preset lithographic pattern, which includes a one-dimensional lithographic pattern and / or a two-dimensional lithographic pattern. The key positions of each preset photolithography pattern are marked and denoted as Gj, j=1,2,…N.

3. The lithography machine matching method as described in claim 1, characterized in that, On the target lithography machine, based on the lithography OPC model, obtain the target key dimensions corresponding to N key positions of each preset lithography pattern. Specifically, this includes the following steps: The lithography parameters are adjusted sequentially for each preset lithography pattern on the target lithography machine, and the corresponding OPC model is generated. Each preset lithography pattern is simulated, exposed on a lithography machine, and SEM images of the lithography pattern are obtained. Extract the contour of each SEM image, and extract X key dimensions to be adjusted at the target key position in the contour, denoted as Sij, i=1,2,…M, j=1,2,…N, where M is the number of preset lithography patterns.

4. The lithography machine matching method as described in claim 1, characterized in that, The process of fitting an OPC model to the lithography machine to be adjusted, using the target lithography machine as a standard, to obtain the key dimensions to be adjusted corresponding to N key positions in each preset lithography pattern on the lithography machine to be adjusted, specifically includes the following steps: Based on the parameters of the target lithography machine, the parameters of the lithography machine to be tuned are adjusted so that the lithography OPC model of the lithography machine to be tuned matches the lithography OPC model of the target lithography machine. The lithography machine to be adjusted is simulated to obtain the corresponding simulation model, and the key dimensions to be adjusted corresponding to the key positions in the preset lithography pattern are obtained from the simulation model.

5. The lithography machine matching method as described in claim 1, characterized in that: The sensitivity matrix of the lithography machine to be tuned is obtained by perturbing the input parameters of the lithography machine to be tuned.

6. The lithography machine matching method as described in claim 5, characterized in that, The process of perturbing the input parameters of the lithography machine to be tuned to obtain the sensitivity matrix specifically includes the following steps: Adjust any adjustable parameter P of the lithography machine to be tuned. Using the target key dimension of the key position obtained by the target lithography machine as the standard, model and calculate the target key dimension of the key position. Let the key dimension to be tuned at the j-th key position Gj be CDj. The sensitivity of CDj to the adjustable parameter P is: The parameters before matching are δP, which represents the minute change in P, and M represents the number of preset lithographic patterns. By combining multiple adjustable parameters P1, P2...PN, the sensitivity matrix is ​​obtained. N is a positive integer.

7. The lithography machine matching method as described in claim 6, characterized in that, Based on the sensitivity matrix, the overall evaluation function is established, which includes the following steps: Based on the sensitivity matrix, different parameters are adjusted to obtain the changes in the key dimension to be adjusted under small adjustments of different parameters. These changes are then summed to obtain the cost value of each key dimension to be adjusted; cost is the adjusted error, which is the change in the key dimension to be adjusted; the formula for cost is: ; The overall evaluation function is obtained by combining the evaluation functions of each adjustable parameter; the formula is: .

8. The lithography machine matching method as described in claim 1, characterized in that, The process involves adjusting the parameters of the lithography machine to be tuned based on the overall evaluation function and simulating a preset lithography pattern. The key dimensions to be measured are obtained from the simulation model, and it is determined whether the obtained key dimensions match the target key dimensions. If they match, the adjustment of the lithography machine to be tuned ends. If they do not match, the overall evaluation function is further optimized using image errors to obtain an optimized evaluation function. The lithography machine to be tuned is then adjusted using the optimized evaluation function. Specifically, this includes the following steps: The preset lithography pattern is simulated using the adjusted lithography machine; The absolute value of the difference between the value of the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine is compared with a preset threshold. If the absolute value of the difference between the value of the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the value of the target key dimension in the image obtained by the target lithography machine is less than or equal to the threshold, then it is determined that the lithography machine to be adjusted and the target lithography machine are matched. If the absolute value of the difference between the key dimension to be adjusted in the simulation model obtained by the lithography machine to be adjusted and the target key dimension in the image obtained by the target lithography machine is greater than the threshold, then the two images are judged to be mismatched, and further optimization is needed to obtain the optimization evaluation function.

9. The lithography machine matching method as described in claim 7, characterized in that, The resulting optimization evaluation function after introducing the penalty function is as follows: ; As a penalty factor, used for regulation exist The proportion in.

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