Substrate Transfer Scheduling for Semiconductor Batch Processing
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Solution Overview
Problem
Batch cleaning process systems for semiconductor wafers face inefficiencies in throughput due to overlapping schedules of apparatuses, leading to unoccupied periods and decreased utilization, especially when processing multiple lots sequentially with a constant recipe.
Innovation Solution
A substrate processing system with independently controlled container transfer apparatus, substrate access area operations, and handling apparatus, allowing for adjusted timing schedules to overlap transfer operations of subsequent lots, optimizing the use of unoccupied periods and improving transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a constant recipe is used for sequential processing of multiple lots, then the process control remains simple, but the throughput decreases due to apparatus idle time and schedule overlaps
Solution Approach 1:
The system dynamically adjusts the process recipe and operation timing for each lot based on the current state of apparatuses. The control section individually adjusts operation timings of the FOUP transfer apparatus, access area operations, and wafer handling apparatus to eliminate idle time and prevent schedule overlaps, transforming the static constant recipe into a dynamic adaptive scheduling system
Solution Approach 2:
The control section monitors the operational status of all apparatuses in real-time and uses this feedback information to adjust subsequent lot scheduling decisions. By detecting when apparatuses become available and when schedule conflicts may occur, the system optimizes the timing of container transfers and wafer operations to maximize throughput
2Productivity
If the FOUP transfer apparatus operates independently without coordinated scheduling, then the transfer operations are simple, but unoccupied periods occur leading to decreased utilization
Solution Approach 1:
The control system segments the overall process into independently controllable operation sequences for different apparatuses (FOUP transfer apparatus, access area operations, wafer handling apparatus). By dividing the control into discrete, manageable segments with defined interfaces, the system achieves coordinated scheduling without requiring complex interdependent control of all apparatuses simultaneously
Solution Approach 2:
The control section performs preliminary scheduling and timing adjustments before executing transfer operations. By pre-coordinating the timing of container transfers, lid operations, and wafer handling in advance, the system ensures that apparatuses are ready to operate without idle time while maintaining relatively simple individual apparatus controls
Data Source
AI summary
A substrate processing system includes a control section configured to control a series of transfer operations and preset to control operation of a container transfer apparatus, operation at a substrate access area, and operation of a substrate handling apparatus independently of each other. The control section includes a schedule creating portion configured to create a transfer schedule by individually adjusting operation timing of the container transfer apparatus, operation timing at the substrate access area, and operation timing of the substrate handling apparatus such that, in a state while a first lot of substrates are treated in the processing system, but the container transfer apparatus and the substrate access area are unoccupied, a container with a second lot of unprocessed substrates stored therein is transferred onto the substrate access area, thereby minimizing total transfer time.