MEMS Flow Sensor Mounting and Coating for Fast Gas Control
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Solution Overview
Problem
Conventional mass flow controllers (MFCs) used in manufacturing systems have slow response rates, making them impractical for applications requiring precise gas control and timing, such as semiconductor fabrication processes.
Innovation Solution
The use of a micro-electromechanical systems (MEMS) device with a free-standing sensing element directly in the gas flow path, coupled with a processing device for fast feedback control, addresses the limitations of traditional MFCs by providing rapid and accurate flow feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If thermal MFC is used to measure and control gas flow, then flow control capability is provided, but response rate is slow (100 milliseconds or longer)
Solution Approach 1:
The patent replaces thermal-based flow sensing with a mechanical MEMS-based flow sensor that directly measures gas flow dynamics. The MEMS device uses a suspended structure with proof mass that responds to gas flow forces, providing mechanical measurement instead of thermal measurement, thereby achieving faster response rates while maintaining control precision
Solution Approach 2:
The patent implements dynamic feedback control using the fast-response MEMS sensor to continuously monitor gas flow and dynamically adjust the mass flow controller in real-time. This dynamic measurement and control approach enables response times under 100 milliseconds, resolving the contradiction between fast response and precise control
2Measurement precision
If conventional MFC is used for gas flow control, then basic flow measurement is achieved, but transient response is too slow for precise timing requirements
Solution Approach 1:
The patent incorporates a fast-response MEMS flow sensor upstream that provides advance flow measurement data before the main control action is needed. This preliminary measurement capability allows the control system to anticipate and prepare for flow adjustments, reducing overall response time while maintaining measurement precision
Solution Approach 2:
The patent implements a dual-feedback control architecture where the MEMS sensor provides high-speed feedback for transient response control, while the conventional MFC provides precision feedback for steady-state accuracy. This combined feedback system achieves both fast response and precise measurement without sacrificing either requirement
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 solution enables fast transient response (less than 1 millisecond) and precise control of gas flow rates, overcoming the limitations of conventional MFCs and meeting the requirements of advanced manufacturing processes.
Implementation Method 1
a free-standing sensing element disposed directly in a flow path of the gas flow channel
Implementation Method 2
The electrodes are disposed on the interface region, and the free-standing sensing element is suspended at the sensor region and electrically coupled to the electrodes
Data Source
AI summary
Disclosed herein are embodiments of a sensor device, systems incorporating the same, and methods of fabricating the same. In one embodiment, a sensor device comprises a free-standing sensing element, such as a micro-electromechanical system (MEMS) device. The sensor device further comprises a metallic band to facilitate mounting the MEMS device to a mounting plate. The sensor device further comprises a conformal coating on a least a portion of a sensor region of the sensor device.