N2 Stocker Monitoring for Wafer Nitrogen Charging Control
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Solution Overview
Problem
The existing process for monitoring and managing air pressure and gas concentration in a 12-inch wafer storage system is cumbersome and inefficient, involving multiple systems (N2STKFDCMESMCS) that complicates timely and accurate determination of nitrogen charging and supplementing needs, potentially leading to wafer scrapping due to environmental issues.
Innovation Solution
A method where the Manufacturing Control System (MCS) directly monitors gas concentration and air pressure data, automates nitrogen charging and supplementing based on set times, and controls ex-warehouse operations to ensure compliance with storage standards, reducing the process to N2STKMCSMES.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing four-system process (N2STK-FDC-MES-MCS) is used for monitoring and managing air pressure and gas concentration, then comprehensive monitoring and control can be achieved, but the process becomes cumbersome and inefficient
Solution Approach 1:
The patent merges the functions of FDC (fault detection and classification system) and MCS (manufacturing control system) into a unified monitoring and control process. The MCS directly collects air pressure and concentration data from N2STK, eliminating the need for separate FDC system intervention and reducing the number of systems involved from four to three, thereby simplifying the process while maintaining comprehensive monitoring capabilities
2Measurement precision
If MES only manages N2STK shelf area while MCS manages specific shelf locations, then accurate location identification is improved, but system coordination complexity increases
Solution Approach 1:
The patent segments the management responsibilities between MES and MCS in a clear hierarchical manner: MES manages the overall N2STK shelf area while MCS manages specific shelf locations. This segmentation allows each system to focus on its designated scope, improving location identification precision while the standardized interface between systems reduces coordination complexity
3Reliability
If nitrogen charging time is extended to ensure proper gas concentration, then wafer storage quality is improved, but productivity decreases due to longer storage time requirements
Solution Approach 1:
The patent implements real-time feedback monitoring of air pressure and gas concentration by MCS directly collecting data from N2STK. This continuous feedback allows the system to dynamically adjust nitrogen charging operations, ensuring wafer storage quality requirements are met while minimizing unnecessary charging time, thus optimizing the balance between quality and productivity
4Loss of time
If direct MCS monitoring of air pressure and concentration is implemented, then response time is improved, but data collection complexity increases
Solution Approach 1:
The patent extracts the data collection function from the FDC system and assigns it directly to MCS. By taking out the air pressure and concentration data collection from the four-system chain and having MCS collect it directly, the response time is improved while the data collection complexity is managed through MCS's existing capabilities rather than adding new complex interfaces
Data Source
AI summary
A method for monitoring gas concentration and air pressure data of a N2-stocker (N2STK) for storing 12-inch semiconductor wafer is provided, and the method comprises: placing a wafer in the N2STK, and inquiring MES about a nitrogen charging time and a longest nitrogen supplementing interval time of the wafer by MCS; replying with the nitrogen charging time by the MES, and starting nitrogen charging after the wafer is warehoused; starting nitrogen charging time counting by the MCS, during the period thereof, if there is an ex-warehouse or warehouse-transfer requirement of the wafer, refusing to execute same by the MCS, and forbidding ex-warehouse or warehouse transfer; if the wafer is stored in the N2STK for a long time, issuing a nitrogen charging instruction again by the MCS to perform a nitrogen charging operation on the wafer; and performing an ex-warehouse operation on the wafer after nitrogen charging is completed.