Substrate Processing Apparatus Mixed Solution Recovery Control
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Solution Overview
Problem
The concentration of the first processing liquid in substrate processing systems can become undesired due to inaccurate recovery and reuse of mixed solutions, leading to inefficiencies and excess consumption of the first processing liquid.
Innovation Solution
A substrate processing apparatus with a retaining tank, recovery route, discarding route, supply route, switching unit, and controller that controls the flow of mixed solutions to recover and reuse them accurately, ensuring the concentration of the first processing liquid remains stable by switching between recovery and discarding routes based on predetermined intervals and recovery rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If mixed solution is recovered and reused to reduce consumption of the first processing liquid, then the consumption of the first processing liquid is reduced, but the concentration of the first processing liquid in the tank becomes undesired due to inaccurate recovery
Solution Approach 1:
The patent changes the control parameter from simple recovery volume to time-based segmented recovery control. By dividing the recovery process into three time intervals (first time interval for initial flushing, second time interval for controlled recovery at predetermined recovery rate, third time interval for final flushing), the system maintains both high recovery efficiency and precise concentration control of the first processing liquid.
Solution Approach 2:
The switching controller monitors the elapsed time and automatically switches between different recovery modes (first recovery mode during first time interval, second recovery mode during second time interval, third recovery mode during third time interval). This feedback-based time-controlled switching ensures the recovery rate is precisely maintained at the predetermined rate during the critical second time interval, preventing concentration deviation.
2Manufacturing precision
If already-used mixed solution is recovered with high accuracy, then the concentration of the first processing liquid can be maintained, but the system complexity increases due to multiple routes and switching mechanisms
Solution Approach 1:
The patent segments the recovery system into distinct functional components: retaining tank for storing the first processing liquid, mixing unit for combining liquids, multiple recovery routes (first recovery route, second recovery route, third recovery route) for different recovery phases, and a switching unit for routing control. This segmentation allows each component to perform its function independently, simplifying the overall control logic despite the multiple routes.
Solution Approach 2:
The switching unit dynamically changes the flowing destination of the supplied liquid based on the current time interval and recovery mode. The system transitions from the first recovery route to the second recovery route to the third recovery route in sequence, with the switching controller adjusting the routing in real-time based on elapsed time and recovery rate requirements, optimizing the recovery process without requiring complex manual intervention.
Data Source
AI summary
A recovery route returns, to a retaining tank, mixed solution supplied to a substrate processing unit. A discarding route discards the supplied mixed solution to a place other than the retaining tank. A switching controller causes the supplied mixed solution to flow into the discarding route during a time interval until a first time interval has elapsed from a time point when the substrate processing unit starts to supply the mixed solution; causes the supplied mixed solution to flow into the recovery route during a time interval until a second time interval, which is decided based on a predetermined recovery rate, has elapsed after the first time interval elapses; and causes the supplied mixed solution to flow into the discarding route during a time interval until supply of the mixed solution has been ended from a time point when the second time interval elapses.