Piezoelectric Mass Flow Controller with Segmented Stacks
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Solution Overview
Problem
Existing mass flow controllers struggle to precisely control a wide range of flow rates and occupy significant facility space, complicating substrate processing operations in semiconductor manufacturing.
Innovation Solution
A mass flow controller utilizing a single piezoelectric actuator with multiple piezoelectric stack assemblies, controlled by different voltages, to achieve precise control of flow rates through fine and coarse modes, simplifying facility design and reducing space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple actuators are used to control different flow rate ranges, then flow rate control precision is improved, but device complexity increases
Solution Approach 1:
The piezoelectric actuator is divided into multiple independent piezoelectric stack assemblies (first, second, and third stacks), each capable of independent actuation. This segmentation allows different stacks to handle different flow rate ranges, achieving high precision control across the entire range while maintaining a single integrated actuator structure.
Solution Approach 2:
The control system dynamically selects which piezoelectric stack assembly to activate based on the target flow rate. For small flow rate adjustments, the first piezoelectric stack is used for fine control. For larger adjustments, the second or third stacks are activated. This dynamic selection optimizes both precision and response time across different operating conditions.
2Adaptability or versatility
If multiple actuators are deployed for wide range control, then flow rate control range is improved, but facility occupying area increases
Solution Approach 1:
Multiple piezoelectric stack assemblies that would traditionally require separate actuators are merged into a single integrated piezoelectric actuator structure. The first, second, and third piezoelectric stacks are arranged in parallel within one actuator housing, sharing common mechanical components and control electronics, thereby reducing the overall space required while maintaining the ability to control a wide flow rate range.
Solution Approach 2:
The single piezoelectric actuator is designed to perform multiple functions through its different piezoelectric stack assemblies. The same actuator can handle both fine flow rate adjustments (using the first stack) and coarse flow rate changes (using the second or third stacks), eliminating the need for multiple specialized actuators and reducing facility space requirements.
3Measurement precision
If multiple actuators are used for precise control, then control precision is improved, but facility complexity increases
Solution Approach 1:
The control system merges multiple piezoelectric stack assemblies into a single integrated actuator unit with unified control electronics and mechanical interface. This consolidation reduces the number of separate control circuits and mechanical connections required, simplifying the overall facility while maintaining the precision benefits of multiple stacks through selective activation.
4Device complexity
If a single actuator is used for wide range control, then facility simplicity is improved, but flow rate control precision deteriorates
Solution Approach 1:
The piezoelectric actuator is segmented into multiple independent piezoelectric stack assemblies with different capacitance values and actuation characteristics. This internal segmentation allows a single actuator to provide both fine precision control (using the first stack with appropriate capacitance) and coarse range control (using the second or third stacks), resolving the contradiction between simplicity and precision.
Solution Approach 2:
Different piezoelectric stack assemblies are designed with different electrical parameters (capacitance values) and mechanical parameters (stroke lengths). By selecting which stack to activate based on the required flow rate change magnitude, the system achieves both fine precision control for small adjustments and wide range control for large adjustments, all through a single actuator structure.
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
Enables precise control of flow rates across a wide range, simplifies facility layout, and reduces space occupancy, enhancing substrate processing efficiency.
Implementation Method 1
a piezoelectric actuator connected to the flow control valve and configured to drive the flow control valve
Data Source
AI summary
Disclosed are mass flow controllers of a substrate processing apparatus, flow control methods the substrate processing apparatus, and substrate processing methods. The flow control method comprises receiving a mode selection signal, controlling a flow control valve under a first mode to allow a flow rate of fluid to change by a first flow rate, and controlling the flow control valve under a second mode to allow the flow rate of fluid to change by a second flow rate. The step of controlling the flow control valve under the first mode includes applying a first voltage to a first piezoelectric stack assembly of a piezoelectric actuator connected to the flow control valve. The step of controlling the flow control valve under the second mode includes applying a second voltage to a second piezoelectric stack assembly disposed on the first piezoelectric stack assembly. The second voltage is different from the first voltage.