Pressure-Based Mass Flow Controller for Bleed-Down and Flow Stability
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Solution Overview
Problem
Current Mass Flow Controllers (MFCs) in semiconductor wafer manufacturing lack precision, leading to inconsistencies in chemical delivery to process chambers, affecting production yield, repeatability, and uniformity due to inadequate control over fluid flow rates and pressure bleed-down during shutdowns.
Innovation Solution
The implementation of high precision sensors, including semiconductor-based pressure and position sensors, in combination with upstream and downstream valves, allows for precise control of fluid flow rates by minimizing bleed-down time and optimizing response time, using algorithms that adjust valve positions and flow rates based on real-time data and predetermined values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current state of the art MFCs are used, then device complexity is reduced, but manufacturing precision and measurement precision deteriorate
Solution Approach 1:
The patent combines multiple functions into a single integrated MFC system: high precision semiconductor pressure sensors, position sensors, upstream and downstream valves, and diagnostic algorithms are merged into one unified device. This integration enables precise flow control and comprehensive diagnostics without requiring multiple separate systems, thereby improving manufacturing precision while managing device complexity.
Solution Approach 2:
The patent replaces traditional mechanical flow control mechanisms with semiconductor-based pressure sensors and electronic control systems. The use of semiconductor sensors and algorithm-based control (rather than purely mechanical adjustments) enables higher precision measurement and control, improving manufacturing precision through electronic and computational methods.
2Adaptability or versatility
If MFCs operate at multiple set points with shutdown and restart, then adaptability improves, but reliability deteriorates due to flow inconsistencies
Solution Approach 1:
The patent implements feedback control using high precision pressure sensors that continuously monitor flow conditions. The diagnostic algorithms process sensor data in real-time and adjust valve positions to maintain accurate flow rates during shutdowns, restarts, and transitions between set points. This feedback mechanism ensures reliability by compensating for flow inconsistencies that occur during operational changes.
Solution Approach 2:
The patent uses diagnostic algorithms to detect and address potential flow issues before they affect manufacturing precision. The system performs preliminary diagnostics during shutdown and restart sequences, adjusting parameters in advance to ensure consistent flow rates when operation resumes, thereby maintaining reliability during adaptive operations.
3Measurement precision
If high precision sensors and advanced diagnostics are implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent designs the sensor and control system to perform multiple functions: pressure sensing, position sensing, flow measurement, and diagnostic analysis are all integrated into the same system components. The semiconductor pressure sensors and control algorithms serve both measurement and control purposes, reducing the need for separate dedicated components and thereby managing device complexity while maintaining high measurement precision.
4Manufacturing precision
If valve stroke adjustments are made frequently for flow control, then manufacturing precision improves, but loss of time increases due to bleed-down delays
Solution Approach 1:
The patent uses real-time feedback from pressure and position sensors to optimize valve adjustments. The diagnostic algorithms analyze sensor data to determine the minimal necessary valve stroke changes, reducing unnecessary adjustments and minimizing bleed-down time while maintaining manufacturing precision. The system learns from operational patterns to optimize response time.
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 enhances the accuracy and consistency of fluid flow, improving wafer manufacturing yield and ensuring wafer-to-wafer uniformity and process reproducibility by reducing unwanted flow perturbations and enabling early warning/prognostic analysis.
Implementation Method 1
at least one semiconductor based pressure sensor in fluid communication with the at least one upstream location and the at least one downstream location
Implementation Method 2
a valve assembly in fluid communication with at least one upstream location and at least one downstream location
Data Source
AI summary
A mass flow controller for controlling flow rate comprising a controller, a valve assembly, and at least one pressure sensor, valve position sensor, and temperature sensor; wherein, at least one of the sensors is a semiconductor based sensor. The valve assembly is in fluid communication with at least one upstream location and at least one downstream location. The at least one pressure sensor is in in fluid communication with the at least one upstream location and the at least one downstream location. The valve assembly can comprise at least one piezoelectric or solenoid valve. The controller is communicable coupled with the valve assembly and at least one of the sensors. The controller determines at least one of: pressure; position; and temperature. The controller further causes an adjustment to valve stroke based on an actual fluid flow rate and at least one of the pressure, position, temperature, and a predetermined value.