Fitting-Based Defect Detection for Semiconductor Wafer Inspection
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Solution Overview
Problem
Current defect detection techniques in semiconductor manufacturing, particularly for ultra-large scale integration, face challenges in precision and uniformity due to the need for high-speed, low-resolution initial inspections followed by detailed reviews, which can lead to inefficiencies and inaccuracies in identifying defects on semiconductor wafers.
Innovation Solution
A method and system for computerized defect detection that involves acquiring a distribution of comparison values between pixels in an inspection image and corresponding reference values, fitting an approximation function, setting a defect detection criterion, and determining the presence of defects based on this criterion, with options for using a Parabola function and weighting common and outlier comparison values differently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed low-resolution inspection is used in the first phase, then inspection speed is improved, but measurement precision deteriorates
Solution Approach 1:
The inspection process is divided into two distinct phases: a first phase using high-speed low-resolution inspection to quickly identify suspected defect locations, and a second phase using detailed high-resolution inspection to confirm defects. This segmentation allows each phase to optimize for its specific function, resolving the contradiction between speed and precision.
Solution Approach 2:
The first phase performs preliminary inspection to generate a defect map identifying suspected locations before the second phase conducts thorough analysis. This preliminary action filters out obvious non-defects early, allowing the second phase to focus resources on areas requiring detailed examination, thus maintaining both speed and precision.
2Reliability
If two phase inspection review procedure is implemented, then defect detection reliability is improved, but loss of time increases
Solution Approach 1:
The second phase inspection is applied selectively only to suspected locations identified by the first phase, rather than performing detailed inspection on the entire wafer. This local quality approach concentrates inspection resources where they are most needed, maintaining high reliability while reducing overall inspection time.
Solution Approach 2:
The first phase performs a more extensive initial scan to identify all potential defect locations, while the second phase performs partial detailed inspection only on suspected areas. This combination ensures comprehensive defect detection reliability while minimizing the time spent on detailed inspection of already-confirmed defects.
Data Source
AI summary
A system configured to detect defects in an inspection image generated by collecting signals arriving from an article, the system comprising a tangible processor which includes: (i) a distribution acquisition module, configured to acquire a distribution of comparison values, each of the comparison values being indicative of a relationship between a value associated with a pixel of the inspection image and a corresponding reference value; (ii) a fitting module, configured to fit to the distribution an approximation function out of a predefined group of functions; and (iii) a defect detection module, configured to: (a) set a defect detection criterion based on a result of the fitting; and to (b) determine a presence of a defect in the inspection image, based on the defect detection criterion.