AI Wafer Defect Detection System Using Dynamic Inspection Switching
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Solution Overview
Problem
The complexity of semiconductor photolithography processes leads to various types of wafer defects, necessitating a quick and accurate detection method to prevent yield decreases in semiconductor manufacturing.
Innovation Solution
An AI system integrating a machine vision CIS device and deep learning for real-time monitoring, which includes a server configuration to learn and distinguish defects, control equipment operations, and perform total inspections, thereby preventing continuous defect occurrence by immediately stopping affected equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If periodic sampling inspection is used, then productivity is maintained, but measurement precision and defect detection accuracy deteriorate
Solution Approach 1:
The inspection system dynamically adjusts the inspection method based on defect occurrence. When defects are detected, the system transitions from periodic sampling inspection to total inspection, and can further escalate to stopping equipment operation. This dynamic adaptation allows the system to maintain high productivity during normal operation while ensuring high detection accuracy when defects occur.
Solution Approach 2:
The AI system continuously monitors inspection results and provides feedback to adjust the inspection strategy. When defects are detected in periodic sampling, the system triggers a switch to total inspection method, and if defects persist, it triggers equipment stoppage. This feedback mechanism ensures that measurement precision is maintained without permanently sacrificing productivity.
2Measurement precision
If total inspection method is implemented, then measurement precision improves, but productivity decreases
Solution Approach 1:
The system implements total inspection dynamically and temporarily, only when defects are detected in periodic sampling. Once the defect cause is identified and corrected, the system can return to periodic sampling inspection, thereby maintaining high productivity while achieving high detection accuracy when needed.
Solution Approach 2:
The system alternates between periodic sampling inspection and total inspection based on defect occurrence. During normal operation, periodic sampling maintains productivity. When defects occur, total inspection is activated temporarily to ensure complete detection, then the system returns to periodic sampling, creating a periodic cycle that balances both productivity and detection accuracy.
3Reliability
If equipment operation is not stopped upon defect detection, then productivity is maintained, but reliability deteriorates due to continuous defect occurrence
Solution Approach 1:
The system dynamically determines whether to stop equipment based on defect patterns. For isolated defects, periodic sampling continues without stoppage, maintaining productivity. For recurring or systematic defects, the system triggers equipment stoppage to prevent continuous defect occurrence, thereby improving reliability while minimizing impact on productivity.
Solution Approach 2:
The AI system automatically analyzes defect patterns and makes decisions about equipment stoppage without external intervention. When defects are detected, the system self-determines whether to maintain operation or stop equipment based on the severity and pattern of defects, enabling autonomous reliability management while preserving productivity when safe to do so.
Data Source
AI summary
An artificial intelligence (AI) system for wafer defect detection may include a CIS device configured to mount to track equipment and to transmit a scanned image of a wafer to a database; and a server configured to learn the scanned image, to distinguish a defect of the wafer for each defect category, to learn defects that occur in exposure equipment and the track equipment for each type, and to perform real-time monitoring. The server is configured to change a periodic sampling inspection to a total inspection method through the CIS device in response to occurrence of the defect in the wafer.