EUV Light Source Configuration for Finer Linewidths
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Solution Overview
Problem
Existing EUV light sources struggle to optimize the EUV illumination system for semiconductor circuits with finer linewidths, leading to inefficiencies in EUV exposure processes.
Innovation Solution
A method of configuring an EUV light source that involves obtaining mask pattern information, generating a top-hat illumination system using Fourier approximation, selecting a combination of EUV point light sources based on established rules, and performing simulations to optimize the entire EUV illumination system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional EUV light source configuration methods are used, then the EUV illumination system can be configured, but the optimization time is excessive and the system performance is insufficient for finer linewidths
Solution Approach 1:
The patent segments the continuous EUV light source configuration process into discrete steps: obtaining mask pattern information, generating top-hat illumination system, storing aerial image information, selecting point light source combinations, and performing simulations. This segmentation enables systematic optimization and reduces overall configuration time while maintaining precision for finer linewidths.
Solution Approach 2:
The patent performs preliminary actions by pre-generating the top-hat illumination system based on Fourier approximation of the mask pattern and pre-storing aerial image information for various point light sources. These preliminary configurations are prepared before the actual exposure process, significantly reducing the time required during production while ensuring optimal performance for the specific mask pattern.
2Manufacturing precision
If the EUV illumination system is optimized for better performance, then the NILS improves, but the configuration complexity increases
Solution Approach 1:
The patent uses Fourier approximation to create a simplified copy or representation of the mask pattern in the frequency domain. This approximation enables the generation of the top-hat illumination system without requiring complex direct calculations from the original mask pattern, thus improving NILS while reducing configuration complexity.
Solution Approach 2:
The patent optimizes NILS by changing key parameters in the illumination system configuration, specifically the selection and combination of EUV point light sources corresponding to pupil mirrors. By adjusting these parameters based on the stored aerial image information and established rules, the system achieves higher NILS without proportionally increasing configuration complexity.
3Manufacturing precision
If a comprehensive simulation of the entire EUV illumination system is performed, then the optimization accuracy improves, but the computational time increases
Solution Approach 1:
The patent performs preliminary simulations and calculations to generate and store aerial image information for various EUV point light sources before the comprehensive system simulation. This preliminary action prepares reference data that accelerates the final optimization process, maintaining high accuracy while reducing the time required for the complete simulation of the EUV illumination system.
Data Source
AI summary
A method of configuring an extreme ultraviolet (EUV) light source includes obtaining first information about a mask pattern, generating a top-hat illumination system for the mask pattern based on a Fourier approximation, storing second information about aerial images of EUV point light sources that correspond to pupil mirrors, selecting a combination of the EUV point light sources according to established rules, and performing a simulation on an entire EUV illumination system, based on the selected combination of the EUV point light sources.