Method and device for optimizing mask parameters

Patent metadata

Field	Value
Publication number	US-12222641-B2
Application number	US-202117773668-A
Country	US
Kind code	B2
Filing date	Nov 8, 2021
Priority date	Oct 29, 2021
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

The present disclosure provides a method for optimizing mask parameters, and the method includes: acquiring a test pattern, light source parameters, and initial mask parameters, the initial mask parameters including a mask thickness and an initial mask sidewall angle; generating multiple sets of candidate mask parameters according to the initial mask sidewall angle in the initial mask parameters; the multiple sets of candidate mask parameters including different mask sidewall angles and the same mask thickness; obtaining an imaging contrast of each set of candidate mask parameters based on the test pattern and the light source parameters; and selecting an optimal mask sidewall angle from the multiple sets of candidate mask parameters according to the imaging contrasts. By generating multiple sets of candidate mask parameters including different mask sidewall angles and the same mask thickness, and simulating these sets of candidate mask parameters respectively, the imaging contrast of each set of candidate mask parameters is obtained, so that the optimal mask sidewall angle is found according to the imaging contrasts. Therefore, by optimizing the mask parameters of the multi-layer film lens structure, the imaging contrast can also be significantly improved, and the imaging resolution can be improved.

First claim

The invention claimed is:

1. A method for optimizing mask parameters, the method comprising:
acquiring a test pattern, light source parameters, and initial mask parameters, the initial mask parameters comprising a mask thickness and an initial mask sidewall angle;
generating multiple sets of candidate mask parameters according to the initial mask sidewall angle in the initial mask parameters; wherein the multiple sets of candidate mask parameters comprising different mask sidewall angles and the same mask thickness;
obtaining an imaging contrast of each set of candidate mask parameters based on the test pattern and the light source parameters; and
selecting an optimal mask sidewall angle from the multiple sets of candidate mask parameters according to the imaging contrasts.

2. The method according to claim 1 , wherein the generating multiple sets of candidate mask parameters according to the initial mask sidewall angle in the initial mask parameters comprises:
starting from the initial mask sidewall angle, generating one mask sidewall angle every other preset step until the generated mask sidewall angle is larger than a preset sidewall angle; and
forming each generated mask sidewall angle and the mask thickness into a set of candidate mask parameters.

3. The method according to claim 1 , wherein the obtaining an imaging contrast of each set of candidate mask parameters based on the test pattern and the light source parameters comprises:
for each set of candidate mask parameters, under the condition of the set of candidate mask parameters, obtaining a maximum light intensity and a minimum light intensity of an aerial image formed in a photoresist coated on a base layer by using the test pattern and the light source parameters; and
determining the imaging contrast of the set of candidate mask parameters according to the maximum light intensity and the minimum light intensity.

4. The method according to claim 1 , wherein the selecting an optimal mask sidewall angle from the multiple sets of candidate mask parameters according to the imaging contrasts comprises:
determining the mask sidewall angle in the candidate mask parameters corresponding to a maximum value of the imaging contrast, as the optimal mask sidewall angle.

5. A device for optimizing mask parameters, the device comprising:
an acquisition module, which is configured to acquire a test pattern, light source parameters, and initial mask parameters, the initial mask parameters comprising a mask thickness and an initial mask sidewall angle;
a candidate parameter generation module, which is configured to generate multiple sets of candidate mask parameters according to the initial mask sidewall angle in the initial mask parameters; wherein the multiple sets of candidate mask parameters comprising different mask sidewall angles and the same mask thickness;
a simulation module, which is configured to obtain an imaging contrast of each set of candidate mask parameters based on the test pattern and the light source parameters; and
an optimal value selection module, which is configured to select an optimal mask sidewall angle from the multiple sets of candidate mask parameters according to the imaging contrasts.

6. The device according to claim 5 , wherein the candidate parameter generation module is specifically configured to: starting from the initial mask sidewall angle, generate one mask sidewall angle every other preset step until the generated mask sidewall angle is larger than a preset sidewall angle; and form each generated mask sidewall angle and the mask thickness into a set of candidate mask parameters.

7. The device according to claim 5 , wherein the simulation module is specifically configured to: for each set of candidate mask parameters, under the condition of the set of candidate mask parameters, obtain a maximum light intensity and a minimum light intensity of an aerial image formed in a photoresist coated on a base layer by using the test pattern and the light source parameters; and determine the imaging contrast of the set of candidate mask parameters according to the maximum light intensity and the minimum light intensity.

8. The device according to claim 5 , wherein the optimal value selection module is specifically configured to: determine the mask sidewall angle in the candidate mask parameters corresponding to a maximum value of the imaging contrast, as the optimal mask sidewall angle.

Assignees

• Inst Of Microelectronics Cas

Inventors

• He Jianfang
• Wei Yayi
• Su Yajuan
• Dong Lisong
• Zhang Libin
• Chen Rui
• Ma Le

Classifications

• G03F1/70

  Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging · CPC title

• G03F7/705

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title

• G03F1/44 Primary

  Testing or measuring features, e.g. grid patterns, focus monitors, sawtooth scales or notched scales · CPC title

• G03F1/00 Primary

  Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof · CPC title