Hole Pattern Detection Using Distance Maps and Center Pixel Search
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Solution Overview
Problem
Existing pattern inspection methods struggle to accurately and efficiently detect hole patterns in images, particularly in ultrafine patterns used in semiconductor manufacturing, due to the complexity and small dimensions involved.
Innovation Solution
A method that extracts outline position candidates for hole patterns, generates distance maps for each pixel in a region, identifies center pixel candidates, and searches for groups of outline positions that satisfy predetermined conditions, thereby improving the accuracy and speed of hole pattern detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional outline extraction methods are used to detect hole patterns, then measurement precision is improved, but processing time increases significantly
Solution Approach 1:
The patent segments the hole pattern detection task into multiple discrete steps: generating distance maps in different directions, extracting center pixel candidates, and then searching for outline positions. This segmentation allows each step to be optimized independently, improving overall processing efficiency while maintaining detection accuracy.
Solution Approach 2:
The patent performs preliminary actions by generating distance maps for all pixels in the region before extracting outline positions. These distance maps are pre-calculated for multiple directions, which accelerates the subsequent outline extraction process by avoiding repeated calculations during the detection phase.
2Manufacturing precision
If high-accuracy hole pattern extraction is performed, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The inspection process is divided into distinct modular steps: distance map generation, center pixel extraction, and outline position search. This segmentation enables parallel processing of multiple hole patterns simultaneously, improving productivity without sacrificing the high accuracy required for ultrafine pattern inspection.
Solution Approach 2:
The patent changes the approach from direct pixel comparison to using distance maps as an intermediate parameter representation. This parameter transformation enables more efficient calculation and comparison operations, achieving both high precision and improved processing speed for pattern inspection.
3Measurement precision
If detailed outline extraction is performed for each hole pattern, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential information needed for accurate outline detection by generating distance maps that represent the spatial relationship from each pixel to the nearest center pixel candidate. This extraction approach simplifies the data structure while preserving the geometric information necessary for precise outline position determination.
Data Source
AI summary
Method for searching a hole pattern in image includes extracting, from an image where a hole pattern is formed, plural outline position candidates serving as candidates for plural positions where an outline of the hole pattern passes, generating, for each pixel in a region including the plural outline position candidates, a distance map which defines, for each of plural directions, a distance from each of the plural outline position candidates to each of pixels arrayed in a target direction of the plural directions, extracting a candidate for a center pixel of the hole pattern by using the distance map generated for each direction, and searching, in the plural outline position candidates, a group of outline position candidates which satisfies a predetermined condition in the case of using the candidate for the center pixel as a starting point, as plural outline positions where the outline of the hole pattern passes.