Exposure Apparatus Mask Pattern Optimization via MSD Compensation
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Solution Overview
Problem
Existing exposure apparatuses face challenges in achieving precise image formation due to stage vibrations and asynchrony, leading to blurred images and inadequate exposure conditions, as current methods do not account for the impact of moving standard deviation (MSD) on image lateral shifts.
Innovation Solution
A computer-readable storage medium storing a program that calculates and adjusts mask patterns and exposure conditions based on image lateral shift information, using parameters such as light source shape and mask pattern dimensions to optimize image formation, even in the presence of MSD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If exposure conditions and mask patterns are determined by optimization calculations without considering MSD, then calculation simplicity is maintained, but image formation precision deteriorates due to unaccounted lateral shifts
Solution Approach 1:
The patent applies preliminary action by pre-calculating the moving standard deviation (MSD) of the stage and using it to adjust exposure conditions and mask patterns before actual exposure. The system calculates lateral shift amounts based on predicted stage movements and compensates for these shifts in advance by modifying the mask pattern or exposure parameters, thereby eliminating the need for complex real-time adjustments during exposure while maintaining high image formation precision
Solution Approach 2:
The patent changes physical parameters by adjusting exposure conditions (such as exposure amount, focus, and illumination conditions) and mask pattern parameters (such as line width and pattern shape) based on the calculated MSD. By varying these parameters according to the predicted stage movement, the system compensates for lateral shifts and maintains precise image formation without increasing computational complexity during the exposure process
2Ease of operation
If stage vibrations and asynchrony are not compensated, then exposure process simplicity is maintained, but image quality deteriorates due to blurred images
Solution Approach 1:
The patent uses copying by creating a virtual model of the stage movement characteristics (MSD) and using this copy to predict and compensate for lateral shifts. Instead of directly measuring and correcting actual stage vibrations during exposure, the system creates a computational model of the stage behavior and uses this model to pre-adjust exposure conditions and mask patterns, thereby maintaining operational simplicity while improving image quality
Solution Approach 2:
The system performs preliminary measurement and characterization of stage vibration characteristics to establish the MSD model before production exposure. By capturing the stage movement behavior in advance and using it to pre-calculate compensation parameters, the system eliminates the need for complex real-time vibration compensation mechanisms during actual exposure, maintaining ease of operation while significantly improving image quality
3Productivity
If mask patterns and exposure conditions are optimized without MSD consideration, then processing time is reduced, but device yield deteriorates due to inadequate image formation
Solution Approach 1:
The patent applies preliminary action by calculating the MSD and using it to optimize mask patterns and exposure conditions before mass production. The system performs the compensation calculations once during the setup phase based on stage characterization data, and then uses these pre-determined parameters for all subsequent exposures. This approach eliminates the need for time-consuming iterative adjustments during production while ensuring high device yield through accurate image formation
Solution Approach 2:
The patent changes the optimization parameters by incorporating MSD-based lateral shift compensation into the mask pattern design and exposure condition selection. Instead of optimizing for ideal stationary conditions, the system optimizes parameters that account for predicted stage movements, thereby achieving both fast processing and high device yield. The parameter changes are made once during setup and then consistently applied throughout production
Data Source
AI summary
A computer readable storage medium is provided, storing a computer-executable program for causing a computer to determine at least one of mask pattern and exposure condition of an exposure apparatus having an illumination optical system for illuminating a mask with light from a light source and a projection optical system for projecting the mask pattern onto a substrate. The program causes the computer to perform calculation of an image of a pattern on an object plane of the projection optical system using information about lateral shift of an image caused by the exposure apparatus, and determination of at least one of the exposure condition and the mask pattern based on a calculation result.