Dual-Loop Pressure Regulator for CMP Stability and Response
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Solution Overview
Problem
The existing pressure regulators for CMP (Chemical Mechanical Polishing) apparatuses face challenges in achieving both stability and responsiveness of pressure regulation, where improving stability compromises responsiveness and vice versa.
Innovation Solution
A pressure regulator system incorporating a PID controller and a regulator controller that employs dual-loop control, using a first pressure sensor and regulator controller for initial quick response to pressure command changes and a second pressure sensor and PID controller for stable long-term pressure regulation, ensuring both quick response and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-loop pressure control system is used, then the device complexity is reduced, but the pressure stability and responsiveness cannot be improved simultaneously
Solution Approach 1:
The control system is segmented into two independent loops: a outer loop using a first pressure sensor and regulator controller for stable long-term pressure regulation, and an inner loop using a second pressure sensor and PID controller for rapid pressure adjustments. This segmentation allows each loop to be optimized for its specific function, resolving the contradiction between stability and complexity.
Solution Approach 2:
The patent introduces an intermediary mechanism where the two pressure control loops interact through a hierarchical structure. The outer loop sets the target pressure, and the inner loop executes rapid adjustments to achieve the target. This intermediary relationship allows the system to benefit from both the stability of the outer loop and the responsiveness of the inner loop without requiring a completely complex integrated system.
2Stability of the object's composition
If pressure regulation prioritizes stability, then pressure fluctuations are reduced, but the response time to pressure changes increases
Solution Approach 1:
The patent merges two different control approaches (proportional control and PID control) into a unified dual-loop system. The proportional control loop handles stable long-term regulation, while the PID control loop handles rapid transient responses. By combining these two control strategies, the system achieves both pressure stability and fast response speed simultaneously.
Solution Approach 2:
The control system dynamically switches between different control modes based on the operational state. The outer loop provides continuous stable regulation, while the inner loop dynamically responds to rapid pressure changes. This dynamic operation allows the system to maintain stability during normal operation while achieving fast response when pressure adjustments are needed.
3Speed
If pressure regulation prioritizes responsiveness, then pressure changes are tracked quickly, but pressure stability deteriorates
Solution Approach 1:
The control system dynamically allocates control functions between two loops based on the situation. The inner PID loop provides rapid responsiveness when pressure changes occur, while the outer proportional loop maintains overall stability. This dynamic division of labor allows the system to achieve fast response without sacrificing stability, as each loop operates in its optimal performance range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This dual-loop control mechanism allows for rapid pressure adjustments while maintaining stability, enhancing the overall performance of the pressure regulation system in CMP apparatuses.
Implementation Method 1
a first pressure sensor configured to measure the pressure regulated by the pressure regulation valve
Implementation Method 2
a second pressure sensor located downstream of the first pressure sensor configured to measure a second pressure value of the fluid
Implementation Method 3
a pressure regulation valve configured to regulate a pressure of a fluid supplied from a fluid supply source
Implementation Method 4
This dual-loop control mechanism allows for rapid pressure adjustments while maintaining stability
Data Source
AI summary
A pressure regulator capable of improving both stability of pressure and responsiveness to an input signal is disclosed. A PID controller is configured to stop producing a corrective command value from a point in time when a pressure command value has changed until a PID control starting point and to produce the corrective command value after the PID control starting point. A regulator controller is configured to control operation of a pressure regulation valve so as to eliminate a difference between the pressure command value and a first pressure value from the point in time when the pressure command value has changed until the PID control starting point, and to control the operation of the pressure regulation valve so as to eliminate a difference between the corrective command value and the first pressure value after the PID control starting point.