Exposure Apparatus Stage Control Residual Suppression
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Solution Overview
Problem
In photolithography processes, especially for semiconductor device manufacturing, focus alignment residuals occur due to varying focus correction values across exposure regions, leading to stage control residuals during substrate driving.
Innovation Solution
An exposure apparatus that measures surface positions at multiple points in each exposure region, calculates an approximate surface shape, and controls substrate stage driving based on a correction value from a previously exposed region if the approximate surface information falls within a predetermined range, thereby reducing stage control residuals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If focus correction values are varied for each exposure region to improve focus alignment accuracy, then focus alignment precision is improved, but stage control residuals are generated due to frequent driving corrections
Solution Approach 1:
The patent changes the parameter of focus correction value from being region-specific to being shared across multiple regions. By determining a single focus correction value based on measurement points from multiple exposure regions and applying it uniformly, the system maintains focus alignment precision while eliminating stage control residuals that would result from frequent driving corrections.
2Measurement precision
If focus correction is performed frequently for each exposure region, then focus alignment accuracy is improved, but synchronization accuracy between measurement and exposure deteriorates due to stage driving residuals
Solution Approach 1:
The patent merges the focus correction process across multiple exposure regions by determining a single correction value that applies to all regions. This combining approach maintains focus alignment accuracy while eliminating the synchronization errors that would result from performing separate focus corrections for each region.
Data Source
AI summary
An exposure apparatus including an obtainment unit configured to obtain, for each of a plurality of exposure regions on a substrate, surface positions in a height direction in the exposure region, and a control unit configured to control, based on the obtained surface positions, driving of a substrate stage in the height direction, wherein the control unit obtains an approximate surface approximately representing a cross-sectional shape of a surface of the exposure region from the obtained surface positions obtained, and for a first exposure region for which information related to the approximate surface does not exceed a predetermined range, controls the driving based on a correction value related to the driving obtained from an approximate surface approximately representing a cross-sectional shape of a surface of the exposure region that has been exposed prior to the first exposure region.