Alternating Scanning Direction Allocation for Semiconductor Overlay Accuracy
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Solution Overview
Problem
The existing imprint techniques face challenges in achieving high throughput and overlay accuracy when scanning exposure is performed on multiple adjacent shot regions in the same scanning direction, leading to decreased productivity and increased overlay errors.
Innovation Solution
A method that allocates alternating scanning directions to adjacent first regions, ensuring that the combination of scanning directions is common across multiple second regions, which are formed by aggregating the first regions, thereby improving throughput and overlay accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If scanning exposure is performed on multiple adjacent shot regions in the same scanning direction, then overlay accuracy is improved, but throughput significantly decreases
Solution Approach 1:
The substrate is divided into multiple shot regions, and scanning directions are allocated differently to adjacent first regions. Specifically, scanning directions are alternated in the direction perpendicular to the scanning direction, so that adjacent shot regions are scanned in different directions. This segmentation of scanning directions allows the reticle stage to remain in position longer, improving throughput while maintaining overlay accuracy through proper direction allocation.
Solution Approach 2:
The scanning direction is made dynamic and adaptable rather than fixed. The system determines scanning directions for multiple first regions based on the layout of shot regions and allocates directions to minimize reticle stage returns. This dynamic allocation strategy allows optimization of both throughput and overlay accuracy by adapting the scanning pattern to the specific substrate layout.
2Productivity
If scanning directions are alternated in the direction perpendicular to the scanning direction, then throughput is improved, but the complexity of scanning direction allocation increases
Solution Approach 1:
The system changes the parameter of scanning direction allocation by determining directions based on the geometric arrangement of shot regions. By establishing clear rules for direction allocation (alternating in the perpendicular direction), the complexity is managed through systematic parameter assignment rather than complex real-time calculations, making the solution implementable while improving throughput.
Data Source
AI summary
A method includes first step of forming first pattern in each of first region of a substrate by using scanning exposure apparatus, and second step of forming second pattern in each second region of the substrate having undergone the first step. Each second region includes at least two first regions, and in the first step, scanning direction in the scanning exposure apparatus is allocated to each of the at least two first regions. Combination of the scanning directions allocated to the at least two first regions is common to the second regions. The combination is determined such that the scanning directions of at least first regions, of the at least two first regions, which are arranged in a direction perpendicular to the scanning directions are alternately changed one by one.