Lithography Alignment Using Split Mark Measurement for Overlay Accuracy
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Solution Overview
Problem
Current substrate processing systems face challenges in achieving high overlay accuracy in semiconductor device manufacturing due to distortion in shot area arrangements caused by processing steps like resist coating, development, etching, and CMP, which requires more precise detection of alignment marks without reducing throughput.
Innovation Solution
A substrate processing system with a measurement device that measures position information of multiple marks on a substrate and an exposure apparatus that uses this information to control the position for precise exposure of divided areas, allowing for accurate alignment and correction of nonlinear distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of sample shot areas is increased to improve overlay accuracy, then manufacturing precision is improved, but throughput is reduced
Solution Approach 1:
The patent divides the wafer surface into multiple shot areas, each containing alignment marks. By segmenting the measurement task across multiple discrete locations rather than measuring the entire wafer uniformly, the system can efficiently collect sufficient data points for high-precision overlay correction while maintaining fast processing speed through parallel measurement capability
Solution Approach 2:
The system performs preliminary measurement of alignment mark positions before the actual exposure process. By pre-measuring and storing the position information of multiple alignment marks across different shot areas, the system prepares correction data in advance, enabling fast exposure operations without compromising overlay accuracy
2Manufacturing precision
If the number of marks to be detected is increased to achieve higher overlay accuracy, then manufacturing precision is improved, but the complexity of the measurement process increases
Solution Approach 1:
The patent employs a universal measurement approach where the same measurement device and methodology are used to detect all alignment marks across different shot areas. This multi-functional measurement system handles various mark positions and configurations using a standardized process, reducing operational complexity while enabling detection of a large number of marks for high-precision correction
Solution Approach 2:
The system implements feedback by measuring the actual positions of alignment marks, comparing them with reference positions, and using the detected deviations to calculate and apply correction values. This closed-loop feedback mechanism systematically processes large amounts of mark position data to achieve high overlay accuracy without requiring complex manual intervention
Data Source
AI summary
A lithography system is provided with: a measurement device measuring position information of marks on a substrate held in a first stage; and an exposure apparatus on a second stage, the substrate for which the position information measurement for the marks has been completed, performs alignment measurement to measure position information for part of marks selected from among the marks on the substrate, and performs exposure. The measurement device measures position information of marks on the substrate to obtain higher-degree components of correction amounts of an arrangement of divided areas, and the exposure apparatus measures position information of a small number of marks on the substrate to obtain lower-degree components of the correction amounts of the arrangement of the divided areas and exposes the plurality of divided areas while controlling the position of the substrate by using the obtained lower-degree components and the higher-degree components obtained by the measurement device.