Pattern Matching Using Design Data Regions of Interest
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Solution Overview
Problem
Existing pattern matching techniques for semiconductor devices fail to accurately align images due to shape discrepancies between design data and real patterns, particularly in repetitive patterns, leading to incorrect identification and increased operator intervention, which hampers automation and efficiency in semiconductor inspection processes.
Innovation Solution
A computer program and pattern matching apparatus that utilize Regions of Interest (ROIs) generated through expansion processing of edge information from design data and real images, enabling proper alignment and matching by comparing these ROIs, even in cases of shape discrepancies, and allowing for early detection and recovery from matching errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If template matching is carried out using design data and real pattern images, then position alignment can be achieved, but shape discrepancies between design data and real patterns cause matching failures and incorrect identification
Solution Approach 1:
The patent divides the pattern matching process into multiple stages: initial template matching to obtain rough alignment, followed by edge information extraction and ROI comparison for precise alignment. This segmentation allows the system to handle shape discrepancies by using different matching strategies at different stages, improving both precision and reliability.
Solution Approach 2:
The patent introduces edge information and Regions of Interest (ROIs) as intermediary elements between the template and the pattern. Instead of directly comparing the entire template with the pattern, the system extracts edge information and compares ROIs, which serves as a mediator that is more robust to shape variations and discrepancies.
2Measurement precision
If smoothing processing is carried out on design data and real pattern images to eliminate shape differences, then matching accuracy improves, but operator intervention increases and automation decreases
Solution Approach 1:
The patent implements automatic determination of matching success or failure by comparing ROI similarity between the template and the pattern. The system autonomously evaluates whether the matching meets predetermined criteria and proceeds with subsequent processing without requiring operator judgment, thereby maintaining high automation while ensuring accurate matching.
3Productivity
If conventional pattern matching methods are used for repetitive patterns, then processing speed is maintained, but incorrect identification occurs due to asymmetrical side walls and shape variations
Solution Approach 1:
The patent applies different quality requirements to different regions of the pattern by focusing comparison on critical Regions of Interest (ROIs) rather than the entire pattern. This local quality approach allows the system to tolerate variations in non-critical areas while ensuring accurate matching in critical regions, improving identification accuracy without sacrificing processing speed.
Data Source
AI summary
It is an object of the present invention to provide a semiconductor inspection apparatus capable of well carrying out position alignment and correctly determining whether the position alignment has been carried out successfully or has ended in a failure without operator interventions even if an inspected image is an image having few characteristics as is the case with a repetitive pattern or the inspected image is an image having a complicated shape.The semiconductor inspection apparatus includes means for imaging a shape on a wafer or on an exposure mask; means for storing an image inspected by the imaging means; means for storing design data of the semiconductor circuit corresponding to a position on the wafer or on the exposure mask which are to be imaged by the imaging means; means for storing a design-data image obtained as a result of converting the design data into an image; means for generating a design-data ROI image by converting an interest drawing region found from a relative crude-density relation of a shape included in the design-data image into an image; and a position alignment section configured to carry out position alignment on the inspected image and the design-data image. The semiconductor inspection apparatus makes use of the design-data ROI image in order to identify a position at which the inspected image and the design-data image match each other or compute the degree of coincidence.