Pattern Inspection Apparatus Using Segmented Tolerance for Semiconductor Defect Detection
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Solution Overview
Problem
Current pattern inspection methods in semiconductor production are inefficient in detecting clear abnormalities such as bridging or disconnection in electronic device patterns, often requiring extensive time and prone to false judgments due to deformation and image inclination issues.
Innovation Solution
A pattern inspection apparatus and method that utilizes reference pattern data and image pickup data to generate tolerance values, allowing for precise detection of abnormalities by comparing the object pattern to a corrected reference pattern, focusing on part detection, deformation analysis, and abnormality judgment within defined tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of measuring points is increased to improve measuring precision, then measurement accuracy is improved, but inspection time becomes excessively long
Solution Approach 1:
The patent segments the pattern inspection into two distinct approaches: (1) detailed measurement at specific critical points for high precision, and (2) rapid beltlike region inspection for quick defect detection. This segmentation allows the system to apply different inspection strategies to different areas, achieving both high precision where needed and fast inspection overall.
Solution Approach 2:
The patent implements partial action by performing full detailed measurement only on critical regions where defects are most likely to occur, while using rapid inspection for other areas. The beltlike inspection region focuses measurement resources on the most critical portions of the pattern, avoiding excessive measurement in areas where it would waste time.
2Reliability
If the beltlike inspection region and tolerance are expanded to detect disconnection, then disconnection detection capability is improved, but clear abnormalities such as bridging may be overlooked
Solution Approach 1:
The patent applies local quality by setting different tolerance values for different types of abnormalities. The system uses upper-limit values for detecting disconnections (where larger tolerance helps) and lower-limit values for detecting bridging (where smaller tolerance maintains precision). This localized tolerance adjustment allows the same inspection system to effectively detect different defect types without compromising either capability.
Solution Approach 2:
The patent changes the tolerance parameter dynamically based on the inspection context. By switching between upper-limit and lower-limit tolerance values depending on the specific inspection region and suspected defect type, the system adapts its detection sensitivity to optimize both disconnection and bridging detection capabilities.
3Reliability
If the tolerance is expanded to account for pattern deformation, then false positives due to deformation are reduced, but clear abnormalities may be missed
Solution Approach 1:
The patent applies local quality by setting different tolerance values for different regions of the pattern. Critical regions where clear abnormalities are expected to occur use tighter tolerances to maintain detection sensitivity, while non-critical regions use looser tolerances to accommodate normal deformation. This spatially varying tolerance strategy reduces false positives without missing clear defects.
Solution Approach 2:
The patent implements partial action by applying deformation tolerance only where necessary - in regions where pattern deformation is expected but clear abnormalities are not anticipated. In critical regions where bridging or disconnection is likely, the system uses stricter tolerances to ensure clear abnormalities are not missed, applying tolerance selectively rather than uniformly.
4Productivity
If rapid inspection method is used to shorten inspection time, then productivity is improved, but measurement precision and accuracy are reduced
Solution Approach 1:
The patent segments the inspection process into rapid beltlike region inspection for overall defect screening and detailed measurement for precise characterization. This segmentation enables the system to achieve high productivity through rapid initial inspection while maintaining measurement precision through follow-up detailed measurement of suspicious areas.
Solution Approach 2:
The patent performs preliminary rapid inspection of the beltlike region to identify potential defects before conducting detailed measurements. This preliminary action filters out obviously normal patterns quickly, allowing detailed precise measurement to be focused only on regions that require it, thereby achieving both speed and accuracy.
Data Source
AI summary
A pattern inspection apparatus for detecting an abnormality includes a storage, a compensator and an abnormality judger. The storage stores data based on a reference pattern associated with an object pattern as an object to detect an abnormality and including a first pattern edge portion and a second pattern edge portion. The compensator partially compensates a location of the first pattern edge portion to be shrunk or expanded based on the reference pattern such that the first pattern edge portion is to be placed at a location of a third pattern edge portion while the second pattern edge portion maintains the same size. The abnormality judger sets a tolerance based on the location compensated based on the reference pattern, and judges the object pattern as abnormal when an outline of the object pattern is fallen outside of the tolerance.