Wafer Transfer Control for Semiconductor Processing Stability
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Solution Overview
Problem
In semiconductor processing systems, when a processing chamber experiences an abnormality, transferring wafers to another chamber can result in defective products due to unstable conditions, leading to variations in product properties and reduced productivity, as the new chamber may not have completed necessary cleaning or seasoning processes.
Innovation Solution
A control device and method that determines transfer destinations based on the operating state of processing chambers, temporarily evacuates wafers from abnormal chambers, and inhibits transfer to new destinations if the preceding process in those chambers does not meet stability conditions, ensuring stable processing conditions are maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafers are transferred to a processing chamber that has undergone cleaning but not seasoning, then the abnormality in the original chamber is avoided, but the processing conditions become unstable and defective products are generated
Solution Approach 1:
The system performs seasoning processing in advance before transferring wafers to a processing chamber. The control device checks whether seasoning has been completed prior to wafer transfer, ensuring that the chamber is in a stable processing condition before the wafer enters, thereby preventing defective products while maintaining productivity
2Speed
If wafers are transferred to a processing chamber immediately after cleaning, then transfer speed is improved, but the atmosphere in the chamber is unstable and product quality deteriorates
Solution Approach 1:
Seasoning processing is performed as a preliminary step before wafer transfer to ensure the processing chamber atmosphere is stable. The control device verifies that seasoning has been completed before allowing wafer transfer, thus maintaining both transfer speed and product quality
3Productivity
If the transfer route is optimized to use any available processing chamber, then productivity is improved, but the new chamber may not be in a stable condition and defects occur
Solution Approach 1:
The control device continuously monitors the processing chamber conditions including whether cleaning and seasoning have been completed. Based on this feedback information, the control device determines the appropriate transfer destination, ensuring that wafers are only transferred to chambers that have completed all necessary preparation processes, thus maintaining both productivity and processing quality
Data Source
AI summary
A processing system includes process modules, load lock modules, an equipment controller, and a machine controller. The equipment controller controls transfer and processing of wafers in the processing system. A transfer destination determining portion determines the transfer destination of each wafer such that each wafer is sequentially transferred to a normally operating process module. When an abnormality occurs in a process module, an evacuation portion temporarily evacuates to a cassette stage the wafer determined is to be transferred to the abnormal process module and that has not yet been transferred to the abnormal process module. When a new transfer destination of the evacuated wafer is determined, if a process that is performed immediately before processing the evacuated wafer in the processing module as the new transfer destination satisfies a predetermined condition, a transfer inhibition portion inhibits the transfer of the evacuated wafer to the new transfer destination.