Composite Wafer Map Defect Detection for Semiconductor Yield
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Solution Overview
Problem
Semiconductor wafers often suffer from defects on their bottom surfaces due to contamination from particles caused by friction and vibrations during photo processes, leading to defocus problems that degrade product quality and yield.
Innovation Solution
A method and system for detecting initial defects on the bottom surface of wafers by generating a composite wafer map from multiple process operations, sorting defect points into clusters, and identifying the initial process operation where defects occurred based on operation information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple wafer maps are combined to detect initial defects, then defect detection accuracy is improved, but system complexity increases
Solution Approach 1:
The patent segments the wafer inspection process into multiple independent wafer maps, each corresponding to a specific process operation. By dividing the inspection data into separate temporal segments (different process steps), the system can identify initial defects at specific stages without requiring a monolithic complex system. Each wafer map is processed independently and then combined, reducing overall system complexity while maintaining detection accuracy.
Solution Approach 2:
The patent performs preliminary inspection at each process operation to create individual wafer maps before combining them. By conducting defect detection in advance at each stage and storing the results, the system avoids the need for complex real-time analysis during final inspection. This preliminary action approach allows the system to combine pre-processed data from multiple sources, reducing computational complexity while improving detection accuracy.
2Loss of information
If defect points are sorted into clusters to identify initial processes, then defect tracking capability is improved, but processing time increases
Solution Approach 1:
The patent segments defect points into clusters based on their spatial proximity and process operation timing. By organizing defect data into discrete clusters that correspond to specific process stages, the system can quickly identify initial defects without processing all data points sequentially. This segmentation enables parallel processing and reduces overall processing time while maintaining comprehensive defect tracking.
Solution Approach 2:
The patent performs preliminary sorting and clustering of defect points during the data collection phase, rather than performing complex analysis during final inspection. By pre-organizing defect data into clusters with associated process operation information, the system reduces the computational burden during final defect identification, thereby decreasing processing time while preserving complete defect tracking capability.
Data Source
AI summary
A method of detecting defects of a wafer including generating a composite wafer map comprising defect points by combining a plurality of wafer level maps generated by measuring the wafer according to the respective process operations; sorting the defect points according to defect clusters using positions of the defect points included in the composite wafer map; and detecting an initial process operation, from among the respective process operations, in which a defect occurred, using operation information, for each of the defect clusters.