US-20260126732-A1 - METHOD AND APPARATUS FOR DETERMINING PROCESS WINDOW, AND COMPUTER DEVICE

Abstract

Provided are a method and an apparatus for determining a process window and a computer device. A surface plasmon photolithography model corresponding to a surface plasmon photolithography structure with an air layer is established. A simulation is performed based on the surface plasmon photolithography model to determine a photoresist pattern formed via photolithography and a critical dimension in the photoresist pattern. A thickness of the air layer and/or exposure energy in the surface plasmon photolithography model are adjusted and the simulation is performed based on the surface plasmon photolithography model repeatedly, to obtain multiple correspondences between the exposure energy, the thickness of the air layer, and the critical dimension. Based on the correspondences and a tolerance range allowed for a critical dimension between the photoresist pattern and a pattern of a mask layer corresponding to the photoresist pattern, the process window corresponding to the mask layer is determined.

Inventors

• Le Ma
• Yayi Wei
• Lisong Dong
• Yajuan SU

Assignees

• Institute of Microelectronics, Chinese Academy of Sciences

Dates

Publication Date

20260507

Application Date

20251029

Priority Date

20241107

Claims (20)

1. 1 . A method for determining a process window, comprising: a first step of establishing a surface plasmon photolithography model corresponding to a surface plasmon photolithography structure, wherein the surface plasmon photolithography structure comprises a substrate layer, a photoresist layer, an air layer, a metal layer, an insulating layer, and a mask layer which are stacked in sequence; a second step of performing a simulation based on the surface plasmon photolithography model to determine a photoresist pattern formed via photolithography and a critical dimension in the photoresist pattern; a third step of repeatedly adjusting a thickness of the air layer and/or exposure energy in the surface plasmon photolithography model and performing the simulation based on the surface plasmon photolithography model, to obtain a plurality of correspondences between the exposure energy, the thickness of the air layer, and the critical dimension in the photoresist pattern; and a fourth step of determining, based on the correspondences and a tolerance range allowed for a critical dimension between the photoresist pattern and a pattern of the mask layer corresponding to the photoresist pattern, the process window corresponding to the mask layer.
2. 2 . The method according to claim 1 , further comprising: repeatedly adjusting the pattern of the mask layer and performing the first step to the fourth step to determine a plurality of process windows, wherein each of the plurality of process windows corresponds to a pattern of the mask layer; and determining, based on the plurality of process windows, a common process window corresponding to a plurality of patterns of the mask layer.
3. 3 . The method according to claim 1 , wherein the surface plasmon photolithography model comprises a spatial light intensity model and a photoresist model, and the second step of performing a simulation based on the surface plasmon photolithography model to determine a photoresist pattern formed via photolithography and a critical dimension in the photoresist pattern comprises: performing a surface plasmon photolithography simulation via the spatial light intensity model to determine a light intensity distribution in the photoresist layer; and simulating, based on the light intensity distribution, a photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern.
4. 4 . The method according to claim 2 , wherein the surface plasmon photolithography model comprises a spatial light intensity model and a photoresist model, and the second step of performing a simulation based on the surface plasmon photolithography model to determine a photoresist pattern formed via photolithography and a critical dimension in the photoresist pattern comprises: performing a surface plasmon photolithography simulation via the spatial light intensity model to determine a light intensity distribution in the photoresist layer; and simulating, based on the light intensity distribution, a photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern.
5. 5 . The method according to claim 3 , wherein the adjusting the exposure energy in the surface plasmon photolithography model comprises: adjusting a light intensity of incident light in the spatial light intensity model, wherein the light intensity has a one-to-one correspondence with the exposure energy.
6. 6 . The method according to claim 4 , wherein the adjusting the exposure energy in the surface plasmon photolithography model comprises: adjusting a light intensity of incident light in the spatial light intensity model, wherein the light intensity has a one-to-one correspondence with the exposure energy.
7. 7 . The method according to claim 3 , wherein the adjusting the exposure energy in the surface plasmon photolithography model comprises: adjusting the exposure energy for the photoresist layer in the photoresist model.
8. 8 . The method according to claim 4 , wherein the adjusting the exposure energy in the surface plasmon photolithography model comprises: adjusting the exposure energy for the photoresist layer in the photoresist model.
9. 9 . The method according to claim 3 , wherein the performing a surface plasmon photolithography simulation via the spatial light intensity model to determine a light intensity distribution in the photoresist layer comprises: performing, in a first simulation software, the surface plasmon photolithography simulation via the spatial light intensity model to determine the light intensity distribution in the photoresist layer; and the simulating, based on the light intensity distribution, a photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern comprises: simulating, in a second simulation software, based on the light intensity distribution, the photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern.
10. 10 . The method according to claim 4 , wherein the performing a surface plasmon photolithography simulation via the spatial light intensity model to determine a light intensity distribution in the photoresist layer comprises: performing, in a first simulation software, the surface plasmon photolithography simulation via the spatial light intensity model to determine the light intensity distribution in the photoresist layer; and the simulating, based on the light intensity distribution, a photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern comprises: simulating, in a second simulation software, based on the light intensity distribution, the photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern.
11. 11 . The method according to claim 1 , wherein the adjusting a thickness of the air layer and/or exposure energy in the surface plasmon photolithography model comprises: adjusting the exposure energy in the surface plasmon photolithography model based on a first preset variation, and adjusting the thickness of the air layer based on a second preset variation.
12. 12 . The method according to claim 1 , further comprising: repeatedly adjusting a thickness of the metal layer and performing the first step to the fourth step to determine a plurality of process windows, wherein each of the plurality of process windows corresponds to a thickness of the metal layer; and determining a thickness of the metal layer corresponding to a maximum process window among the plurality of process windows, as an optimal thickness of the metal layer of the surface plasmon photolithography structure.
13. 13 . A computer device, comprising a processor and a memory, wherein the memory is configured to store program codes; and the processor is configured to, based on the program codes, perform a first step: establish a surface plasmon photolithography model corresponding to a surface plasmon photolithography structure, wherein the surface plasmon photolithography structure comprises a substrate layer, a photoresist layer, an air layer, a metal layer, an insulating layer, and a mask layer which are stacked in sequence; a second step: perform a simulation based on the surface plasmon photolithography model to determine a photoresist pattern formed via photolithography and a critical dimension in the photoresist pattern; a third step: repeatedly adjust a thickness of the air layer and/or exposure energy in the surface plasmon photolithography model and perform the simulation based on the surface plasmon photolithography model, to obtain a plurality of correspondences between the exposure energy, the thickness of the air layer, and the critical dimension in the photoresist pattern; and a fourth step: determine, based on the correspondences and a tolerance range allowed for a critical dimension between the photoresist pattern and a pattern of the mask layer corresponding to the photoresist pattern, the process window corresponding to the mask layer.
14. 14 . The computer device according to claim 13 , wherein the processor is further configured to, based on the program codes: repeatedly adjust the pattern of the mask layer and perform the first step to the fourth step to determine a plurality of process windows, wherein each of the plurality of process windows corresponds to a pattern of the mask layer; and determine, based on the plurality of process windows, a common process window corresponding to a plurality of patterns of the mask layer.
15. 15 . The computer device according to claim 13 , wherein the surface plasmon photolithography model comprises a spatial light intensity model and a photoresist model, and the processor is further configured to, based on the program codes: perform a surface plasmon photolithography simulation via the spatial light intensity model to determine a light intensity distribution in the photoresist layer; and simulate, based on the light intensity distribution, a photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern.
16. 16 . The computer device according to claim 14 , wherein the surface plasmon photolithography model comprises a spatial light intensity model and a photoresist model, and the processor is further configured to, based on the program codes: perform a surface plasmon photolithography simulation via the spatial light intensity model to determine a light intensity distribution in the photoresist layer; and simulate, based on the light intensity distribution, a photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern.
17. 17 . The computer device according to claim 15 , wherein the processor is further configured to, based on the program codes: adjust a light intensity of incident light in the spatial light intensity model, wherein the light intensity has a one-to-one correspondence with the exposure energy.
18. 18 . The computer device according to claim 16 , wherein the processor is further configured to, based on the program codes: adjust a light intensity of incident light in the spatial light intensity model, wherein the light intensity has a one-to-one correspondence with the exposure energy.
19. 19 . The computer device according to claim 15 , wherein the processor is further configured to, based on the program codes: adjust the exposure energy for the photoresist layer in the photoresist model.
20. 20 . The computer device according to claim 16 , wherein the processor is further configured to, based on the program codes: adjust the exposure energy for the photoresist layer in the photoresist model.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims the priority to Chinese Patent Application No. 202411584831.8, titled “METHOD AND APPARATUS FOR DETERMINING PROCESS WINDOW,” filed on Nov. 7, 2024 with the China National Intellectual Property Administration, which is incorporated herein by reference in its entirety. FIELD The present disclosure relates to the field of semiconductors, and in particular to a method and an apparatus for determining a process window, and a computer device. BACKGROUND With the development of near-field optics, photolithography methods that break through a diffraction limit, exemplified by a surface plasmon (SP) photolithography method, have gradually been realized. By means of surface plasmon photolithography, a photolithographic pattern with a corresponding dimension much smaller than a wavelength of light from a light source can be obtained based on a long light wavelength. However, this is essentially contact photolithography, which is inefficient, and therefore a surface plasmon photolithography structure with an air layer has been further developed. In the surface plasmon photolithography structure having an air layer, a mask layer and a photoresist layer are separated by the air layer, which employs near-field projection photolithography in essence. In this way, similar to conventional projection photolithography, a wafer carried by a wafer stage can be moved to expose different regions of the wafer, thereby greatly improving operation efficiency. In the related art, for the surface plasmon photolithography structure having an air layer, a process window is generally obtained through a manual experiment, which involves constructing a photolithography model manually and setting parameters such as exposure energy. Due to considerable uncertainty inherent in the experiment, the solution wastes a large amount of manpower and resources, and is inefficient. Therefore, how to propose a suitable method for determining a process window is a technical problem to be addressed. SUMMARY In view of this, an objective of the present disclosure is to provide a method and a apparatus for determining a process window, and a computer device. According to the present disclosure, by means of simulation, the process window is determined faster and more accurately, thereby saving materials and time and improving the accuracy of the process window. The solutions are as follows. In one aspect, a method for determining a process window is provided in the present disclosure. The method includes: a first step of establishing a surface plasmon photolithography model corresponding to a surface plasmon photolithography structure, where the surface plasmon photolithography structure includes a substrate layer, a photoresist layer, an air layer, a metal layer, an insulating layer, and a mask layer which are stacked in sequence; a second step of performing a simulation based on the surface plasmon photolithography model to determine a photoresist pattern formed via photolithography and a critical dimension in the photoresist pattern; a third step of repeatedly adjusting a thickness of the air layer and/or exposure energy in the surface plasmon photolithography model and performing the simulation based on the surface plasmon photolithography model, to obtain multiple correspondences between the exposure energy, the thickness of the air layer, and the critical dimension in the photoresist pattern; and a fourth step of determining, based on the correspondences and a tolerance range allowed for a critical dimension between the photoresist pattern and a pattern of the mask layer corresponding to the photoresist pattern, the process window corresponding to the mask layer. In an embodiment, the method further includes: repeatedly adjusting the pattern of the mask layer and performing the first step to the fourth step to determine multiple process windows, where each of the multiple process windows corresponds to a pattern of the mask layer; and determining, based on the multiple process windows, a common process window corresponding to multiple patterns of the mask layer. In an embodiment, the surface plasmon photolithography model includes a spatial light intensity model and a photoresist model, and the second step of performing a simulation based on the surface plasmon photolithography model to determine a photoresist pattern formed via photolithography and a critical dimension in the photoresist pattern includes: performing a surface plasmon photolithography simulation via the spatial light intensity model to determine a light intensity distribution in the photoresist layer; and simulating, based on the light intensity distribution, a photoresist exposure and development via the photoresist model to determine the photoresist pattern formed via the photolithography and the critical dimension in the photoresist pattern. In an embodiment, the adjusting the exposure energy in the surface plasmo