Vaporization Supply Device Pressure Feedback Control
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Solution Overview
Problem
In vaporization supply systems for semiconductor manufacturing, temperature overshoot occurs when gas supply ends, and excessive liquid material is supplied when gas supply starts, due to rapid pressure drops and inadequate heat management.
Innovation Solution
Implementing a method where the vaporizer is heated with a heat amount greater than before feedback control stops when gas flow rate control begins, and reducing heat input before gas supply ends, to maintain stable pressure and prevent temperature overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If feedback control is performed to maintain set temperature in the vaporizer, then temperature stability is improved, but excessive liquid material is supplied when gas supply starts due to rapid pressure drop
Solution Approach 1:
The system performs preliminary action by detecting the start of gas supply and proactively controlling the control valve to close it when pressure drops below the threshold, preventing excessive liquid material supply before it occurs. This anticipatory control resolves the contradiction by acting in advance rather than reacting after temperature instability occurs.
Solution Approach 2:
The system uses feedback control by continuously monitoring the pressure inside the vaporizer and using this information to control the opening/closing of the control valve. The pressure detector provides real-time feedback to the control unit, which adjusts the valve position to maintain pressure within the threshold range, thereby preventing both excessive liquid supply and temperature instability.
2Productivity
If heat amount is increased to maintain vaporization when gas supply starts, then vaporization rate is improved, but temperature overshoot occurs when gas supply ends
Solution Approach 1:
The system performs preliminary action by detecting when gas supply is about to end and proactively controlling the heater to reduce or stop heating before the actual end of gas supply. This prevents temperature overshoot by anticipating the thermal inertia effect that would otherwise cause continued heating after gas flow stops.
Solution Approach 2:
The system applies dynamic control by adjusting the heat amount based on the operational phase - providing higher heat during gas supply to maintain vaporization rate, and reducing or stopping heat before gas supply ends to prevent temperature overshoot. This dynamic adjustment of heating power resolves the contradiction between maintaining productivity and preventing temperature instability.
3Productivity
If pressure threshold is set low to allow continuous operation, then productivity is improved, but temperature control precision deteriorates due to frequent liquid replenishment
Solution Approach 1:
The system uses feedback control by continuously monitoring pressure and using this information to control the control valve timing. The pressure detector provides real-time feedback that enables precise control of liquid material supply, maintaining pressure within the threshold range without excessive replenishment, thereby preserving temperature control precision while enabling continuous operation.
Solution Approach 2:
The system changes the pressure threshold parameter to an appropriate level that balances continuous operation with temperature control precision. By setting the threshold at an optimal value and using pressure-based control timing, the system prevents frequent liquid replenishment that would cause temperature fluctuations, thereby maintaining both productivity and manufacturing precision.
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
Prevents excessive liquid supply at gas start-up and temperature overshoot at gas end, ensuring stable vaporization and efficient heat utilization.
Implementation Method 1
a vaporizer for heating and vaporizing a liquid raw material
Implementation Method 2
heating the inside of the vaporizer to obtain a necessary gas flow rate
Implementation Method 3
a pressure detector for detecting the pressure of the gas vaporized in the vaporizer 2
Data Source
AI summary
A vaporization supply device includes a vaporizer for heating and vaporizing a liquid raw material L, a flow rate controller for controlling a flow rate of the gas supplied from the vaporizer to a gas supply destination, and a controller for heating the inside of the vaporizer to obtain a necessary gas flow rate, and performing a feedback control so that a pressure becomes equal to or higher than a predetermined value. The controller is configured so as to stop the feedback control at the time point when the flow rate control by the flow rate controller starts, then heat the liquid raw material by an amount of heat provided to the vaporizer more than the heat that has already been provided immediately before the feedback control ends, and change to the feedback control after a predetermined time has elapsed from the time point when the flow rate control by the flow rate controller starts.