Silicon Wafer Weak Point Prediction via UCF Index Sampling
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Solution Overview
Problem
Current methods for detecting yield detractors in silicon wafers lack precision and sensitivity, are dependent on expensive EDA vendor pattern classification licenses, and fail to capture geometric variability and complex interactions leading to defects.
Innovation Solution
A method and apparatus for selecting silicon wafer weak points using individual or combined Design for Manufacturing (DFM) decks for feed-forward and feed-back analysis, generating markers and Universal Compact Format (UCF) indexes, and performing UCF-Index-based sampling to identify candidate weak points for inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EDA vendor pattern classification licenses are used for sitelist generation, then pattern classification capability is improved, but licensing cost increases
Solution Approach 1:
The patent replaces expensive EDA vendor pattern classification licenses with a custom-built, cost-effective pattern classification system using machine learning models trained on historical defect data. This disposable-like approach uses affordable computational resources instead of perpetual expensive licenses, achieving similar classification capability without the high licensing cost burden.
Solution Approach 2:
The patent creates a copy of the pattern classification functionality by training machine learning models on harvested patterns from ORC/MRC/DRC markers. Instead of relying on proprietary EDA vendor tools, the system replicates and enhances pattern classification capabilities through custom-trained models, eliminating licensing dependencies while maintaining or improving classification accuracy.
2Loss of time
If only a subset of ORC/MRC/DRC flagged locations are classified for sitelist generation, then processing time is reduced, but coverage completeness deteriorates
Solution Approach 1:
The patent performs preliminary clustering and prioritization of ORC/MRC/DRC flagged locations before full classification. By pre-grouping markers into clusters and identifying high-priority regions based on defect history and pattern severity, the system prepares a structured dataset that enables efficient subsequent processing, allowing comprehensive coverage without excessive processing time.
Solution Approach 2:
The patent segments the design into multiple regions and processes ORC/MRC/DRC markers in distributed parallel clusters. Each cluster independently classifies patterns in its assigned region, then results are aggregated. This segmentation enables full design coverage while reducing the processing burden on any single computational resource, achieving both completeness and efficiency.
3Device complexity
If single EDA vendor tool deck is used for defect prediction, then tool complexity is reduced, but predictive accuracy deteriorates
Solution Approach 1:
The patent merges multiple EDA vendor tool decks (ORC, MRC, DRC, and custom DFM decks) into a unified defect prediction system. By combining the analytical capabilities of multiple tools and integrating their markers into a single machine learning framework, the system achieves superior predictive accuracy that leverages the strengths of each individual tool while maintaining manageable overall complexity through centralized coordination.
Solution Approach 2:
The patent creates a composite defect prediction system that combines multiple analytical approaches and data sources from different EDA tools. Like composite materials that combine different substances to achieve superior properties, the system integrates diverse marker types and classification methods to achieve predictive accuracy greater than any single tool could provide alone.
Data Source
AI summary
A method and apparatus for selecting Si wafer WP based on individual or multiple DFM decks for Si-feed-forward and Si-feed-back analysis are provided. Embodiments include generating markers for a wafer from an individual DFM deck; generating UCF Indexes; determining whether a representative marker corresponding to a UCF is a candidate for WP prediction; extracting markers corresponding to that UCF-Index (UEF data) from a candidate; performing a UCF-Index-based sampling on the extracted UEF data set if a number of markers in the extracted UEF data set is larger than an inspection requirement; adding a location of each marker or group of markers in the extracted UEF data set to a sitelist after the UCF-Index-based sampling; sending the sitelist to a foundry for metrology analysis on sitelist locations; and adding the sitelist locations and corresponding UCF Index and metrology parameters to a design analysis database for analyzing other wafers/UCF Indexes.


