Gas Control System for Film Formation with Flow Rate Limit Detection
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Solution Overview
Problem
Conventional gas control systems for film formation treatments with materials of low vapor pressure experience control limit states where the flow rate of material gas in mixed gas becomes unstable, leading to inefficiencies and potential instability in film formation processes due to the slow vaporization rate and small amounts of material gas generated.
Innovation Solution
A gas control system equipped with a flow rate control unit and a control limit detection unit that adjusts the carrier gas flow rate to maintain stable material gas flow, using flow rate relational data and measurement units to detect and prevent prolonged control limit states by adjusting the carrier gas flow rate based on stored data and real-time measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow rate of carrier gas is increased to increase the flow rate of material gas in mixed gas, then the flow rate of material gas increases up to a limit, but after reaching the limit flow rate, the flow rate of material gas monotonously decreases
Solution Approach 1:
The system pre-stores flow rate relational data showing the relationship between carrier gas flow rate and material gas flow rate before actual film formation. This allows the system to predict and avoid control limit states by referencing pre-acquired data, preventing the instability that would occur if the carrier gas flow rate exceeded the limit where material gas flow rate begins to decrease.
Solution Approach 2:
The control system continuously monitors the actual material gas flow rate and compares it with the target flow rate. When a control limit state is detected (where further increases in carrier gas flow rate would decrease material gas flow rate), the system provides feedback to adjust the carrier gas flow rate accordingly, ensuring stable material gas supply throughout the film formation process.
2Productivity
If the flow rate of carrier gas is controlled to be around the limit flow rate to secure material gas flow rate for low vapor pressure materials, then the material gas flow rate can be maintained, but the system enters a control limit state where further adjustment becomes ineffective
Solution Approach 1:
Flow rate relational data is acquired and stored in advance through preliminary experiments, mapping out the safe operating range before actual film formation. This pre-acquired data includes information about the limit flow rate, allowing operators to set carrier gas flow rates within the controllable range without risking entry into the control limit state during production.
Solution Approach 2:
The control unit continuously compares the set carrier gas flow rate against the flow rate relational data to detect potential control limit states. When approaching the limit where material gas flow rate stabilization becomes difficult, the system provides feedback to adjust the carrier gas flow rate, maintaining ease of operation throughout the process.
3Device complexity
If conventional gas control systems are used for materials with low vapor pressure, then the system structure remains simple, but the vaporization rate cannot catch up with the carrier gas flow rate causing control limit states
Solution Approach 1:
The system performs preliminary acquisition of flow rate relational data by actually supplying carrier gas to the material and measuring the resulting material gas flow rate at various carrier gas flow rates. This pre-characterization of the specific material-carrier gas system allows the simple conventional structure to operate reliably by knowing in advance the safe operating parameters for that specific material.
Solution Approach 2:
During actual film formation, the control unit uses feedback control to maintain carrier gas flow rate within the stable operating range identified through preliminary data acquisition. The system detects control limit states by comparing real-time flow rates against the pre-acquired relational data and adjusts accordingly, maintaining process stability without requiring structural modifications to the conventional system.
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
Enables rapid detection and prevention of control limit states, ensuring stable flow rates of material gas and preventing prolonged instability in film formation treatments by accurately adjusting carrier gas flow rates in response to changes in material gas flow rates.
Implementation Method 1
material gas generated by vaporization of the material
Implementation Method 2
measure an absorbance of the material gas led out from the tank
Data Source
AI summary
The present invention provides a gas control system which introduces carrier gas into a tank containing a material and leads out material gas generated by vaporization of the material from the tank together with the carrier gas, the gas control system being provided with: a flow rate control unit that is configure to control the flow rate of the material gas led out from the tank by adjusting the flow rate of the carrier gas introduced into the tank; and a control limit detection unit that is configured to detect a control limit state and output detection of the control limit state, the control limit state is a state that the adjustment of the flow rate of the carrier gas performed by the flow rate control unit cannot secure the flow rate control of the material gas at a predetermined performance level.