Dynamic Care Areas for Wafer Inspection
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Solution Overview
Problem
Current defect source analysis methods in semiconductor manufacturing are inefficient as they often fail to flag defects detected at earlier steps due to conservative thresholds and do not utilize data from one step to enhance defect detection at subsequent steps, leading to missed defect origins and suboptimal inspection results.
Innovation Solution
A computer-implemented method for determining dynamic micro-care areas that includes acquiring and analyzing inspection results from a first fabrication step to inform and enhance the sensitivity of a second inspection step, allowing for more accurate detection of defects and their origins by correlating noise events, marginal defects, and detected defects across fabrication steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conservative thresholds are used at each inspection step for stability purposes, then inspection stability is improved, but defect detection sensitivity deteriorates
Solution Approach 1:
The patent implements dynamic threshold adjustment by analyzing defect signals from previous inspection steps and modifying thresholds for subsequent steps. The system transitions from static conservative thresholds to dynamic adaptive thresholds that become more sensitive in areas where defects were previously detected, thereby resolving the contradiction between stability and detection sensitivity.
Solution Approach 2:
The system uses feedback from previous inspection steps to adjust inspection parameters for current and future steps. By analyzing defect signals from step 1 and using them to modify inspection thresholds and care areas in step 2, the system creates a closed-loop feedback mechanism that improves defect detection while maintaining overall process stability.
2Device complexity
If data from one inspection step is not used to affect subsequent inspection recipes, then inspection process simplicity is improved, but defect tracking accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by using defect data from previous inspection steps to pre-adjust inspection parameters before the current inspection step. Care areas and thresholds are modified in advance based on historical defect patterns, enabling more accurate defect tracking while maintaining relatively simple process implementation.
3Reliability
If defects are not flagged at earlier inspection steps due to conservative thresholds, then false positive reduction is improved, but defect origin identification deteriorates
Solution Approach 1:
The patent introduces an intermediary processing step that analyzes defect signals from previous inspection steps and uses them to adjust subsequent inspection parameters. This intermediary layer allows the system to maintain conservative thresholds for stability while still capturing defect origin information through the feedback mechanism, preventing information loss without increasing false positives.
Data Source
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AI summary
Various embodiments for determining dynamic care areas are provided.