Multi-Gas Branch Line Flow Control with Dynamic Valve Adjustment
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Solution Overview
Problem
Existing gas supply systems for semiconductor manufacturing struggle to accurately control gas flow ratios across multiple branch lines, especially as silicon wafers increase in size, limiting precise distribution and requiring separate distributors that are limited to fewer channels.
Innovation Solution
Implementing control valves and flow meters on each branch line, connected to a controller that adjusts gas flow by measuring and comparing flow rates to required portions, using various control manners to maintain flow within predetermined ranges, and integrating auxiliary supply lines to manage total flow adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate distributors are used to control gas flow ratios, then gas distribution control is achieved, but the system becomes complex and limited to fewer channels
Solution Approach 1:
The system divides the gas supply into multiple independent branch lines, each equipped with its own control valve and flow meter. This segmentation allows each branch to be controlled independently, achieving precise flow ratio control without requiring a complex centralized distributor structure.
Solution Approach 2:
Each branch line is equipped with a flow meter that provides real-time feedback on the actual gas flow rate to the controller. The controller compares the measured flow with the target flow and adjusts the control valve accordingly, forming a closed-loop feedback system that achieves precise flow ratio control.
2Manufacturing precision
If control valves are adjusted frequently to maintain flow ratios, then flow control precision is improved, but system stability deteriorates due to excessive adjustments
Solution Approach 1:
The controller implements a deadband mechanism where adjustments are only made when the flow deviation exceeds a predetermined threshold range. This partial action approach prevents excessive adjustments for minor fluctuations, maintaining system stability while still achieving sufficient flow control precision.
Solution Approach 2:
The control system dynamically adjusts the control valve opening based on real-time flow measurements. The controller modifies the valve position incrementally, increasing or decreasing the opening rate according to the difference between measured and target flow, creating a dynamic response that balances precision and stability.
3Quantity of substance
If the control valve opening rate is increased to meet higher flow demands, then gas supply capacity is improved, but control precision deteriorates due to larger adjustment units
Solution Approach 1:
The control system dynamically adjusts the valve opening rate based on the magnitude of flow deviation. When the measured flow significantly exceeds the target flow, the controller decreases the opening rate by larger units to quickly reduce flow. When the flow is below target, it increases the opening rate by appropriate units to meet the demand, optimizing both response speed and control precision.
Data Source
AI summary
Provided is a method for multi-supplying gas, the method comprising: installing a control valve and an flow meter on each of a plurality of branch lines branched from a main supply line, in which one or more gases are supplied, and supplying the gas; and providing the gas by adjusting flow of the gas by a controller connected to each of the control valve and the flow meter, wherein the controller has a first control manner, which controls each of the control valves based on a rate of flow measured by the flow meter to required portion flow for each branch line, and the first control manner adjusts an open rate of the control valve if the rate of the measured flow to the required portion flow is not within a predetermined range, and a unit of adjusting the control valve increases or decreases according to a difference between the measured flow and the required portion flow.