Gas Flow Splitting via Impedance-Defined Restrictors
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Solution Overview
Problem
Semiconductor fabrication processes require precise control of gas flows with improved accuracy, lower costs, and faster transient response times, necessitating advanced mass flow control systems that can split process gases into known ratios for selective application in processing chambers.
Innovation Solution
A gas flow control system with a gas flow path, on/off valves, and flow restrictors that determine the ratio of gas flows by impedance, allowing for precise control and splitting of process gases into two separate flows, enabling accurate delivery to different regions within a processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mass flow control apparatuses are used, then gas flow control is achieved, but measurement precision and transient response time are insufficient for advanced semiconductor fabrication processes
Solution Approach 1:
The gas flow path is segmented into multiple independent channels, each with its own flow restrictor and control valve. This segmentation allows for precise control of individual flow paths while maintaining overall system accuracy, resolving the contradiction between measurement precision and response time by enabling independent optimization of each channel.
Solution Approach 2:
The system employs dynamic control through electronically controlled valves that can rapidly adjust flow rates. The control system dynamically responds to process requirements, enabling fast transient response while maintaining precise flow measurement and control accuracy through active feedback and adjustment mechanisms.
2Manufacturing precision
If complex mass flow control systems are implemented to achieve precise flow splitting, then flow control accuracy improves, but device complexity and cost increase
Solution Approach 1:
The flow restrictors are designed with precisely controlled impedance values that inherently determine flow splitting ratios based on gas pressure and flow characteristics. This self-regulating mechanism eliminates the need for complex active control systems, achieving high flow splitting accuracy through passive physical principles while reducing device complexity.
Solution Approach 2:
The system achieves precise flow control by carefully selecting and controlling the impedance parameters of the flow restrictors. By optimizing these physical parameters during design and manufacturing, the system attains high flow splitting accuracy without requiring complex control mechanisms, thus reducing overall system complexity.
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
The system achieves high accuracy and dynamic performance in gas flow control, minimizing transient response times and maintaining precise ratios, even with varying gas mixtures, thereby enhancing semiconductor fabrication processes.
Implementation Method 1
A first flow restrictor having a first flow impedance is operably coupled to the gas flow path and located between the gas inlet and the first gas outlet. A second flow restrictor having a second flow impedance is operably coupled to the gas flow path and located between the gas inlet and the second gas outlet. When both the first and second on/off valves are in a fully open state, a ratio between a first gas flow from the first gas outlet and a second gas flow from the second gas outlet is determined by a ratio of the first flow impedance and the second flow impedance.
Data Source
AI summary
Apparatuses for controlling gas flow are important components for delivering process gases for semiconductor fabrication. In one embodiment, an apparatus for controlling gas flow is disclosed, the apparatus delivering two gas flows at a known ratio. Specifically, the apparatus has first and second on/off valves and first and second flow restrictors. The first and second on/off valves may be altered between an open state and a closed state. When both the first and second on/off valves are in an open state, first and second gas flows are delivered to first and second outlets. The first and second gas flows are provided at a known ratio to one another, this ratio determined by the ratio of the resistance to flow of the first and second flow restrictors.