Substrate Processing Exhaust Gas Dilution Control
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Solution Overview
Problem
The increasing complexity of mixed gases used in semiconductor device manufacturing poses safety and environmental risks during discharge, and existing solutions rely on costly separate gas sensors for explosion prevention.
Innovation Solution
A substrate processing apparatus that measures flow rates of process gases to determine the lower explosion limit and volume percentage of combustible gases, controlling the supply of dilution gases to mitigate explosion risks without the need for separate gas sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate gas sensors are used to monitor mixed gas for explosion prevention, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a control device as an intermediary that calculates explosion risk by processing flow rate data from existing sensors. Instead of directly monitoring gas composition with complex gas sensors, the control device uses flow rate measurements combined with process information to determine combustible gas volume percentages and compare them against lower explosion limits, thereby preventing explosions without adding complex sensing hardware.
Solution Approach 2:
The system uses its own existing flow rate measurement capabilities and process data to self-monitor and self-regulate gas mixture safety. The control device leverages data already being collected for process control purposes, eliminating the need for separate dedicated safety monitoring sensors.
2Reliability
If separate gas sensors are used to monitor mixed gas composition, then explosion risk detection is improved, but manufacturing cost increases
Solution Approach 1:
The control device performs multiple functions: it controls the substrate processing apparatus operation, monitors flow rates for process control, and simultaneously calculates explosion risk assessment. This multi-functionality eliminates the need for separate gas sensors dedicated solely to safety monitoring, reducing overall system cost.
Solution Approach 2:
The system uses its own existing flow rate measurement capabilities and process data to self-monitor and self-regulate gas mixture safety. The control device leverages data already being collected for process control purposes, eliminating the need for separate dedicated safety monitoring sensors.
3Reliability
If dilution gas is supplied to reduce combustible gas volume percentage, then explosion prevention is improved, but gas consumption increases
Solution Approach 1:
The system supplies dilution gas only to the extent necessary to reduce the combustible gas volume percentage below the lower explosion limit. The control device continuously monitors flow rates and adjusts dilution gas supply dynamically, providing just enough dilution to achieve safety without excessive gas consumption.
Solution Approach 2:
The control device dynamically adjusts the flow rate parameters of dilution gas based on real-time measurements of process gas flow rates and calculated combustible gas volumes. By changing the dilution gas flow parameter adaptively rather than using a fixed high flow rate, the system achieves explosion prevention with minimized gas consumption.
Data Source
AI summary
An exhaust method of a substrate processing apparatus, includes: measuring a first flow rate for each of process gases included in a mixed gas supplied to a process chamber; determining, based on the first flow rate, a lower explosion limit of the mixed gas and a first volume percentage of a combustible process gas among the process gases; determining a supply flow rate of a first dilution gas based on the first volume percentage and the lower explosion limit; and supplying, at the determined supply flow rate of the first dilution gas, the first dilution gas to the mixed gas in the process chamber.