Mass Flow Controller Using External Sensor Feedback for Purging
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Solution Overview
Problem
Mass flow controllers in semiconductor manufacturing equipment face challenges in achieving quick purging, accurate flow control, simple flow rate calibration, and control based on pressure or temperature without requiring additional control devices, leading to increased complexity and costs.
Innovation Solution
A mass flow control system where the opening of the flow control valve is controlled based on a detection signal from an external sensor, allowing for operation modes that utilize both internal and external signals to manage flow rates, pressures, and temperatures without the need for separate control devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mass flow controller uses only an internal flow sensor for control, then the control system is simple and self-contained, but the system cannot achieve quick purging or accurate flow control based on external pressure or temperature conditions
Solution Approach 1:
The mass flow controller is designed to accept multiple types of input signals (internal flow sensor signals, external pressure sensor signals, external temperature sensor signals) and process them through a unified control unit. This allows the single device to perform multiple control functions including flow control, pressure-based control, and temperature-based control, eliminating the need for separate control devices for each parameter.
Solution Approach 2:
The patent combines the control functions for flow, pressure, and temperature into a single mass flow controller device. The control unit integrates processing of signals from internal flow sensors and external pressure/temperature sensors, merging multiple control capabilities into one unified system that can operate in different modes depending on the input signals received.
2Manufacturing precision
If separate control devices are added for pressure and temperature control, then accurate control based on these parameters is achieved, but device complexity and costs increase
Solution Approach 1:
The mass flow controller is designed to accept multiple types of input signals (internal flow sensor signals, external pressure sensor signals, external temperature sensor signals) and process them through a unified control unit. This allows the single device to perform multiple control functions including flow control, pressure-based control, and temperature-based control, eliminating the need for separate control devices for each parameter.
3Ease of manufacture
If a mass flow controller is designed as a self-contained unit with internal sensor only, then ease of replacement is maintained, but flow rate calibration becomes complex and requires additional equipment
Solution Approach 1:
The mass flow controller incorporates an internal flow sensor that enables the device to perform self-calibration using its own resources. The control unit processes signals from the internal sensor and can adjust calibration parameters without requiring external calibration equipment, allowing the device to calibrate itself during normal operation or maintenance periods.
4Productivity
If the control system uses only internal flow sensor signals, then the control system is simple, but quick purging cannot be achieved
Solution Approach 1:
The control unit uses feedback from external pressure sensors and temperature sensors to dynamically adjust the flow control valve opening. This feedback mechanism allows the system to respond to real-time pressure and temperature conditions, enabling quick purging operations by rapidly adjusting flow rates based on detected pressure differentials and thermal conditions in the system.
Data Source
AI summary
In a mass flow control system which comprises a first apparatus that is a mass flow controller, an external sensor that is at least one detection means constituting a second apparatus that is an apparatus disposed outside said first apparatus and at least one control section prepared in either one or both of housings of said first apparatus and said second apparatus, and is configured so as to control a flow rate of fluid flowing through a channel, the control section is configured such that opening of a flow control valve can be controlled based on at least an external signal that is a detection signal output from the external sensor.