Associative Gas Supply Control Using Temperature-Linked Pressure Limits
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Solution Overview
Problem
Conventional methods for supplying associative gases like hydrogen fluoride to semiconductor manufacturing apparatuses face challenges in accurately controlling flow rates due to association and dissociation phenomena, which are not adequately addressed by independent temperature and pressure limitations, leading to inefficiencies and potential over- or under-supply issues.
Innovation Solution
A method involving the determination of maximum allowable pressure based on equilibrium vapor pressure data, combined with temperature adjustments and conversion factor analysis, to prevent association and ensure accurate flow control of associative gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature and pressure are limited independently to prevent association, then association is prevented, but the control range is overly restricted and operational flexibility is reduced
Solution Approach 1:
The invention changes from independent temperature and pressure limitations to a coupled parameter control approach. By establishing a maximum allowable pressure that varies with temperature (Pmax(T)) based on equilibrium vapor pressure data, the system allows dynamic adjustment of pressure limits according to actual temperature conditions, thereby preventing association while maintaining operational flexibility.
Solution Approach 2:
The invention introduces dynamic control where the pressure limit is not fixed but varies with temperature. The control system continuously monitors temperature and adjusts the maximum allowable pressure accordingly, creating a dynamic operating envelope that adapts to changing conditions rather than using static independent limits.
2Ease of operation
If flow rate control is performed without considering association phenomena, then control simplicity is maintained, but flow rate measurement accuracy deteriorates
Solution Approach 1:
The invention applies preliminary action by establishing temperature and pressure control measures before flow rate measurement and control. By ensuring the gas remains in a dissociated state through proper T-P control, the subsequent flow rate measurement becomes accurate without requiring complex compensation algorithms or correction factors.
3Device complexity
If conventional flow control methods are used for associative gases, then device complexity is minimized, but flow rate control accuracy deteriorates due to association and dissociation
Solution Approach 1:
The invention implements feedback control by continuously monitoring temperature and pressure and using this information to adjust the maximum allowable pressure setting. The control system compares actual T-P conditions against the Pmax(T) curve and makes real-time adjustments to maintain operation within the safe region, ensuring accurate flow control without requiring complex additional hardware.
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 approach allows for precise and stable supply of associative gases, enhancing the quality and productivity of semiconductor devices by preventing unwanted association and dissociation, thus improving operational efficiency.
Implementation Method 1
molecules of hydrogen fluoride gas associate with each other through hydrogen bonds to form multimers with a degree of association of about 2 to 6
Implementation Method 2
The boiling point of hydrogen fluoride is approximately 20° C. In order to supply hydrogen fluoride in a gaseous state to a semiconductor manufacturing apparatus, it is necessary to heat hydrogen fluoride gas in order to prevent it from liquefying
Data Source
AI summary
The present disclosure determines a maximum allowable pressure Pmax(T) at which it is possible to supply associative gas without causing association, on the basis of equilibrium vapor pressure data acquired for the associative gas, and adjusts the pressure and/or temperature of the associative gas such that the measured pressure of the associative gas does not exceed the maximum allowable pressure. The maximum allowable pressure Pmax(T) is preferably determined on the basis of a stable region of a conversion factor CF of the associative gas as referenced to a calibration gas with which association is unlikely to occur. This makes it possible to stably supply, to a semiconductor manufacturing device, associative gas with which chemical association readily occurs.