CN-116819896-B - Determination method and device of photoetching parameter range, storage medium and computer equipment

CN116819896BCN 116819896 BCN116819896 BCN 116819896BCN-116819896-B

Abstract

The invention discloses a method and a device for determining photoetching parameter budget, a storage medium and computer equipment. The method comprises the steps of determining parameter weights of lithography parameters corresponding to a lithography system, carrying out exposure experiments based on experimental parameters to obtain experimental exposure results, determining parameter combinations in the lithography parameters, determining target weighted normalization sums of the parameter combinations relative to the experimental parameters based on the experimental parameters, the experimental exposure results and the parameter weights, establishing an analysis model aiming at the target weighted normalization sums and the exposure results, carrying out model fitting on the analysis model by utilizing the target weighted normalization sums and the exposure results to obtain a fitting model, calculating an inverse function of the fitting model, calculating a value range of the budget weighted normalization sums based on a preset exposure result range and the inverse function of the fitting model, and determining the value range as the value range of the lithography parameters of the lithography system. The method can improve the calculation accuracy of the photoetching parameter budget range.

Inventors

WEI YAYI
WANG JIASHUO
SU XIAOJING
DONG LISONG
Fan taian
ZHU YIHUA
LI CHEN
SHEN HAO

Assignees

中国科学院微电子研究所

Dates

Publication Date: 20260512
Application Date: 20230529

Claims (9)

1. A method for determining a lithographic parameter budget, applied to a lithographic system, the method comprising: determining parameter weights of lithography parameters corresponding to the lithography system, and carrying out exposure experiments on the lithography system based on preset experimental parameters to obtain experimental exposure results; selecting parameter combinations from the photoetching parameters, and determining target weighted normalization sums of the parameter combinations based on the experimental parameters, the experimental exposure results and the parameter weights; Establishing an analytical model aiming at the target weighted normalization sum and the experimental exposure result, and performing model fitting on the analytical model by utilizing the target weighted normalization sum and the experimental exposure result to obtain a fitting model; calculating an inverse function of the fitting model, calculating a value range of a budget weighted normalization sum based on a preset exposure result range and the inverse function of the fitting model, and determining a budget range of a photoetching parameter of the photoetching system according to the value range; The method for obtaining the parameter weight of the lithography parameter comprises the following steps of: Executing a cyclic process until a preset condition is met, wherein the cyclic process comprises: Selecting one variable parameter from all the lithography parameters, and determining the rest lithography parameters except the variable parameters as ideal parameters in all the lithography parameters; Determining the parameter maximum value of the lithography parameter corresponding to the variable parameter as the parameter value of the variable parameter, and executing exposure operation on the lithography system based on the variable parameter and each ideal parameter to obtain an exposure result; Calculating exposure size variation between the exposure result and a preset ideal exposure result, and parameter variation between a parameter value of the variable parameter and the preset ideal value corresponding to the variable parameter, and calculating parameter weight of the lithography parameter corresponding to the variable parameter based on the exposure size variation and the parameter variation; determining a preset ideal value corresponding to the variable parameter as a parameter value of the variable parameter, and determining the variable parameter and the ideal parameter as the lithography parameter; The preset condition is that each photoetching parameter obtains the corresponding parameter weight.
2. The method of claim 1, wherein the number of parameter combinations is a plurality, wherein the determining a target weighted normalized sum of the parameter combinations based on the experimental parameters, the experimental exposure results, and the parameter weights comprises: Calculating the normalization sum of each lithography parameter in the parameter combination according to the parameter value of the lithography parameter contained in the experimental parameter, the preset ideal value corresponding to each lithography parameter in the parameter combination and the parameter maximum value corresponding to each lithography parameter; Calculating a weighted normalized sum of the parameter combinations from the normalized sum of each of the lithographic parameters in the parameter combinations and the parameter weights; And based on the weighted normalization sum corresponding to each parameter combination and the experimental exposure result, respectively determining the correlation coefficient between the weighted normalization sum corresponding to each parameter combination and the experimental exposure result, and determining the weighted normalization sum corresponding to the largest correlation coefficient as a target weighted normalization sum.
3. The method according to claim 2, wherein calculating the normalized sum of each of the lithography parameters in the parameter set based on the parameter values of the lithography parameters included in the experimental parameters, the preset ideal value for each of the lithography parameters in the parameter set, and the parameter maximum value for each of the lithography parameters comprises: Acquiring parameter values corresponding to the lithography parameters contained in the parameter combination from the experimental parameters; Calculating a first difference value between the parameter value and a preset ideal value corresponding to the photoetching parameter, and calculating a second difference value between a parameter maximum value corresponding to the photoetching parameter and the parameter value; and determining the ratio of the first difference value to the second difference value as the normalized sum of the lithography parameters.
4. The method of claim 2, wherein the determining of the target weighted normalization sum further comprises: calculating the covariance between the weighted normalization sum corresponding to each parameter combination and the experimental exposure result; determining the parameter combination corresponding to the maximum covariance, and determining the parameter combination as a target parameter combination; And determining the weighted normalization sum corresponding to the target parameter combination as the target weighted normalization sum.
5. The method of any one of claims 1-4, wherein model fitting the analytical model using the target weighted normalization sum and the experimental exposure results to obtain a fitted model comprises: Based on the experimental exposure result and the target weighted normalization sum, performing model fitting, and calculating a model coefficient of the analytical model; and obtaining a polynomial function of the analytical model based on the model coefficient, the experimental exposure result and the target weighted normalization sum, and determining the polynomial function as the fitting model.
6. The method according to claim 1, wherein the method further comprises: Distributing parameter values for lithography parameters of the lithography system in the budget range; Performing test exposure operation on the lithography system based on the lithography parameters to obtain a test exposure result of the test exposure operation; Judging whether the test exposure result is within a preset exposure size range, and if the test exposure result is within the preset exposure size range, judging that the budget range meets the precision requirement of the lithography system.
7. A lithographic parameter budget determination apparatus for use in a lithographic system, the apparatus comprising: the weight determining module is used for determining the parameter weight of the lithography parameter corresponding to the lithography system, and carrying out an exposure experiment on the lithography system based on preset experimental parameters to obtain an experimental exposure result, wherein the lithography parameter corresponds to a preset ideal value and a parameter maximum value which are preset respectively; the method for obtaining the parameter weight of the photoetching parameters comprises the steps of executing a cyclic process until a preset condition is met, wherein the cyclic process comprises the steps of selecting one variable parameter from all the photoetching parameters, determining the rest photoetching parameters except the variable parameter as ideal parameters, determining the parameter maximum value of the photoetching parameters corresponding to the variable parameter as the parameter value of the variable parameter, and executing exposure operation on the photoetching system based on the variable parameter and each ideal parameter to obtain an exposure result, calculating the exposure size variation between the exposure result and the preset ideal exposure result, and the parameter variation between the parameter value of the variable parameter and the preset ideal value corresponding to the variable parameter, and calculating the parameter weight of the photoetching parameters corresponding to the variable parameter based on the exposure size variation and the parameter variation; The correlation coefficient module is used for selecting parameter combinations from the photoetching parameters and determining target weighted normalization sums of the parameter combinations based on the experimental parameters, the experimental exposure results and the parameter weights; The model fitting module is used for establishing an analytical model aiming at the target weighted normalization sum and the experimental exposure result, and performing model fitting on the analytical model by utilizing the target weighted normalization sum and the experimental exposure result to obtain a fitting model; The budget determining module is used for calculating an inverse function of the fitting model, calculating a value range of a budget weighted normalization sum based on a preset exposure result range and the inverse function of the fitting model, and determining a budget range of lithography parameters of the lithography system according to the value range.
8. A storage medium having stored thereon a computer program, which when executed by a processor, implements the steps of the method of any of claims 1 to 6.
9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the computer program when executed by the processor implements the steps of the method according to any one of claims 1 to 6.

Description

Determination method and device of photoetching parameter range, storage medium and computer equipment Technical Field The present invention relates to the field of budget resolution technology of high resolution imaging systems, and in particular, to a method and apparatus for determining a lithographic parameter range, a storage medium, and a computer device. Background With the continued development of photolithography, lithographic apparatus are becoming an important device in semiconductor production and manufacturing, which is widely used in the manufacture of large scale integrated circuits. The photoetching process copies the pattern on the mask plate into the photoresist coated on the surface of the silicon wafer in an optical exposure mode, and then the pattern is further transferred onto the silicon wafer through processes such as development, etching and the like. Thus, the state of the art of photolithography systems directly determines the feature sizes in integrated circuit devices, which plays a critical role in the fabrication of large scale integrated circuits. Along with the continuous shrinkage of the process nodes of integrated circuits, the requirements on the photoetching imaging quality are also continuously improved. For an extreme ultraviolet lithography system, the wavelength, bandwidth, polarization and energy stability of a light source have extremely important influence on the exposure result, such as pupil uniformity, symmetry and ellipticity of the illumination system, and the numerical aperture and stray light of a projection system. However, the above parameters are not fixed, and may fluctuate within a certain range due to limitations of production capacity or the like. Therefore, in order to meet the requirements of the lithography exposure result, the variation range of the above parameters needs to be limited to a certain range, that is, the lithography parameters need to be subjected to budget decomposition. However, since there are many lithography parameters, and a change in one lithography parameter may affect a change in another lithography parameter, this may result in an inaccurate definition of the range of variation for a single lithography parameter. Namely, the condition that each parameter is in the single parameter variation range and the exposure result does not meet the process condition under the condition of the combination of various variation parameters exists, so that the calculation accuracy of the budget range of the lithography parameter is poor. Disclosure of Invention In view of this, the present application provides a method, an apparatus, a storage medium and a computer device for determining a lithographic parameter budget, which mainly aims to solve the technical problem of poor calculation accuracy of a lithographic parameter budget range. According to a first aspect of the present invention, there is provided a method of determining a lithographic parameter budget for use in a lithographic system, the method comprising: determining parameter weights of lithography parameters corresponding to the lithography system, and carrying out exposure experiments on the lithography system based on preset experimental parameters to obtain experimental exposure results; selecting parameter combinations from the photoetching parameters, and determining target weighted normalization sums of the parameter combinations based on the experimental parameters, the experimental exposure results and the parameter weights; Establishing an analytical model aiming at the target weighted normalization sum and the experimental exposure result, and performing model fitting on the analytical model by utilizing the target weighted normalization sum and the experimental exposure result to obtain a fitting model; And calculating an inverse function of the fitting model, calculating a value range of a budget weighted normalization sum based on a preset exposure result range and the inverse function of the fitting model, and determining a budget range of a photoetching parameter of the photoetching system according to the value range. According to a second aspect of the invention, there is provided an apparatus for determining a lithographic parameter budget, the apparatus comprising: the weight determining module is used for determining the parameter weight of the lithography parameter corresponding to the lithography system, and carrying out exposure experiments on the lithography system based on preset experimental parameters to obtain experimental exposure results; The correlation coefficient module is used for selecting parameter combinations from the photoetching parameters and determining target weighted normalization sums of the parameter combinations based on the experimental parameters, the experimental exposure results and the parameter weights; The model fitting module is used for establishing an analytical model aiming at the target weighted normalization sum a