Cluster Tool Wafer Transfer Cycle Synchronization
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Solution Overview
Problem
In cluster tool substrate processing systems, the transfer mechanism can only access one process module at a time, leading to conflicts in timing for wafer transfer in and out of process modules with different processing cycles, resulting in reduced throughput and increased processing cycles due to wait times and inefficient operation rates.
Innovation Solution
A substrate processing system with a control unit that sets uniform module cycle periods for all process modules, allowing the transfer mechanism to access them in a sequence matching the processing order, ensuring non-conflicting timing for wafer transfers and optimizing transfer efficiency by offsetting processing cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transfer mechanism accesses process modules sequentially one at a time, then the system structure remains simple and reliable, but timing conflicts occur between modules with different processing cycles, reducing throughput
Solution Approach 1:
The patent implements dynamic cycle time adjustment for different process modules. Each module is assigned a specific cycle time that matches its processing requirements, allowing the system to adapt to varying processing durations without forcing all modules to operate at a uniform pace. This dynamic timing coordination eliminates wait states and timing conflicts while maintaining sequential transfer mechanism operation.
Solution Approach 2:
The system changes the temporal parameters of module operation by assigning different cycle times to different process modules. The control unit coordinates transfers based on these varied cycle times, allowing modules with longer processing requirements to operate on extended cycles while modules with shorter processing times operate on compressed cycles, thereby eliminating idle wait time in the overall system.
2Adaptability or versatility
If process modules operate with different processing cycles, then each module can be optimized for its specific process, but timing conflicts arise that reduce operation rate
Solution Approach 1:
The patent segments the overall processing cycle into module-specific sub-cycles. Each process module operates on its own optimized cycle time tailored to its specific processing requirements, while the control unit coordinates the transfer mechanism to access modules at appropriate intervals. This segmentation allows each module to maintain its optimized processing parameters while the system as a whole achieves improved operation rate through coordinated timing.
Solution Approach 2:
The system employs dynamic cycle time assignment where each process module can operate at its optimal processing speed. The control unit dynamically coordinates transfers based on the specific cycle times of individual modules, allowing the system to accommodate varied processing requirements without compromising the operation rate. This dynamic approach enables both process optimization and high productivity.
3Manufacturing precision
If the transfer mechanism waits for process completion before accessing the next module, then processing accuracy is maintained, but throughput decreases due to idle time
Solution Approach 1:
The control unit performs preliminary coordination of transfer timing based on predicted process completion times. By calculating and scheduling transfers in advance according to each module's cycle time, the system ensures that transfers occur at optimal moments without requiring the transfer mechanism to idle and wait passively. This preliminary action maintains processing accuracy while eliminating unnecessary idle time.
Solution Approach 2:
The system implements feedback-based transfer coordination where the control unit monitors the operational state of each process module and adjusts transfer timing accordingly. This feedback mechanism ensures that transfers are timed to coincide with appropriate moments in the processing cycle, maintaining manufacturing precision while optimizing throughput by preventing idle wait time through real-time coordination.
Data Source
AI summary
In a substrate processing system according to the present invention, module cycle periods at a plurality of process modules PM1 through PM4 connected around a transfer module TM having installed therein a vacuum pressure-side transfer robot RB1, each representing the sum of a wafer stay time including the wafer processing time and an attendant busy time during which the wafer is transferred before and after the wafer stay time, are all set to a uniform length. The vacuum pressure-side transfer robot RB1 takes out a processed wafer Wi and carries a next wafer Wi+1 to be processed next by executing a pick and place operation for each of the process modules PM1 through PM4 during a single access to the process module.