Alignment Mark Position Measurement Beyond Pixel Resolution
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Solution Overview
Problem
Existing position measuring methods in imprint technology fail to accurately track changes in relative positions of alignment marks smaller than pixel resolution, leading to measurement errors in die-by-die alignment.
Innovation Solution
A position measuring method that includes setting processing areas on an image capturing element to capture alignment marks and calculating their positions by shifting these areas in units of one pixel, using a plurality of processing areas for precise alignment measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If processing areas are allocated on the image capturing element in units of pixels, then the measurement system is simple and easy to implement, but it cannot track changes in relative position smaller than pixel resolution
Solution Approach 1:
The patent divides the processing area into multiple sub-processing areas (first processing area and second processing area) that are shifted relative to each other by one pixel. Each sub-processing area independently measures the alignment mark position, and the final position is calculated by combining these measurements. This segmentation allows the system to track position changes smaller than one pixel resolution by distributing the measurement across multiple offset locations.
2Reliability
If a single processing area is used for position measurement, then the processing is fast and efficient, but measurement errors occur when relative position changes are smaller than pixel resolution
Solution Approach 1:
The patent performs preliminary action by setting multiple processing areas with different pixel offsets before the actual measurement. These processing areas are pre-configured to cover different positions, allowing the system to capture position changes that occur between pixel boundaries. This preliminary setup ensures that no position change is missed, improving measurement reliability without requiring complex real-time adjustments during measurement.
Data Source
AI summary
A position measuring method includes an image capturing element for capturing an image of an alignment mark. The method includes first processing of setting processing areas on the image capturing element for capturing an image of the alignment mark and performing position measurement processing, and second processing of calculating a position of the alignment mark on the basis of the processing areas set in the first processing. The position of the alignment mark is calculated using a plurality of the processing areas set by shifting the processing areas from each other in units of one pixel of the image capturing element.