Variable Cycle Flow Rate Control for Semiconductor Liquid Processing
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Solution Overview
Problem
The existing flow rate adjustment mechanisms in liquid processing systems, such as those used in semiconductor wafer processing, deteriorate quickly due to frequent operation, leading to inaccurate flow rate adjustments and a need for frequent replacements, especially under high-demand conditions.
Innovation Solution
A liquid processing apparatus that includes a flow meter, a flow rate adjustment mechanism, and a controller that adjusts the flow rate adjustment cycle based on measured flow rates, extending the life of the mechanism by reducing the frequency of operations when the flow rate is within a preset range and increasing it when deviations occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flow rate adjustment mechanism operates frequently to maintain accurate flow rate adjustments, then the flow rate control precision is improved, but the life of the mechanism deteriorates due to increased mechanical wear
Solution Approach 1:
The patent applies dynamics by making the control cycle variable rather than fixed. The controller dynamically adjusts the control cycle length based on whether the flow rate is within the preset range. When the flow rate is accurate, the control cycle extends to reduce mechanical operations. When the flow rate deviates, the control cycle shortens to improve response. This dynamic adjustment resolves the contradiction between maintaining precision and extending mechanism life.
Solution Approach 2:
The patent changes the parameter of control cycle length based on flow rate conditions. By switching between a first control cycle (when flow rate is within range) and a second control cycle (when flow rate is outside range), the system adapts its operation frequency to actual needs, reducing unnecessary mechanical wear while maintaining control accuracy when required.
2Speed
If the control cycle is shortened to respond quickly to flow rate deviations, then the response speed is improved, but the number of operations of the flow rate adjustment mechanism increases, reducing its life
Solution Approach 1:
The system dynamically adjusts the control cycle length based on operational conditions. When flow rate deviations occur, the controller switches to a shorter second control cycle to achieve rapid response. When flow rate is stable within the preset range, it switches to a longer first control cycle to reduce operations. This dynamic adaptation allows the system to have fast response when needed without continuously subjecting the mechanism to frequent operations.
Solution Approach 2:
The patent implements periodic action with variable periods. Instead of continuous frequent operations, the system uses periodic control cycles that adapt their length based on flow rate conditions. The controller selectively applies the first control cycle (longer period) or second control cycle (shorter period) to match the actual control needs, reducing unnecessary mechanical stress while maintaining responsiveness when deviations occur.
3Measurement precision
If the flow rate adjustment mechanism is operated at a fixed short cycle to ensure continuous accurate control, then the flow rate control accuracy is maintained, but the maintenance frequency increases due to mechanical deterioration
Solution Approach 1:
The patent changes the control cycle parameter based on flow rate conditions rather than maintaining a fixed short cycle. When the flow rate is within the preset range, the controller uses the first control cycle (longer duration) to reduce operations. When the flow rate deviates, it switches to the second control cycle (shorter duration) to restore accuracy. This parameter change approach maintains control accuracy when needed while significantly reducing overall operations and maintenance frequency.
Solution Approach 2:
The system dynamically adapts the control cycle length to actual flow rate conditions, avoiding unnecessary frequent operations during stable periods. This dynamic behavior reduces mechanical wear and deterioration while maintaining control accuracy when deviations occur, thereby reducing maintenance frequency without sacrificing control precision.
Data Source
AI summary
A liquid processing apparatus includes: a substrate processing unit; a supply line that supplies the fluid to the substrate processing unit; a flow meter that measures a flow rate of the fluid flowing through the supply line; a flow rate adjustment mechanism that adjusts the flow rate of the fluid flowing through the supply line; and a controller that control the flow rate adjustment mechanism based on a measurement result of the flow meter. The controller receives the measurement result at a first cycle. When the measurement result of the flow meter indicates that the flow rate of the fluid flowing through the supply line is included in a preset range, the controller causes the flow rate adjustment mechanism to adjust the flow rate of the fluid flowing through the supply line at a cycle having a time interval longer than a time interval of the first cycle.