Pulse Valve Pressure-Drop Feedback for Precise Gas Flow Control
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Solution Overview
Problem
Existing fluid control devices face challenges in achieving high accuracy for flow rate or pressure control during the ON interval of pulse control, particularly in semiconductor manufacturing applications like atomic layer deposition, where simple opening level feedback is insufficient for precise gas flow rates.
Innovation Solution
A fluid control device incorporating a resistor, a pressure sensor, and a control mechanism that uses a pulse signal generator, feedback value calculator, and signal compensator to calculate and compensate for the time integrated value of pressure drop during the ON interval, improving control accuracy by relating the feedback value to the actual flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If simple opening level feedback control is used during pulse control, then the control mechanism is simple and easy to operate, but the flow rate accuracy deteriorates and cannot meet the requirements for atomic layer deposition
Solution Approach 1:
The patent implements a feedback control mechanism that measures the actual flow rate using a flow sensor and compares it with the target flow rate. The control mechanism then adjusts the valve opening level based on the deviation between actual and target flow rates, ensuring high flow rate accuracy while maintaining operational simplicity through automated closed-loop control.
Solution Approach 2:
The patent replaces simple mechanical opening level feedback with an electronic control system that uses flow sensor measurements and electronic signal processing. The control mechanism electronically adjusts the valve based on real-time flow rate data, substituting mechanical feedback with electronic sensing and control to achieve higher precision.
2Productivity
If pulse control with short pulse width is implemented, then the productivity and deposition precision are improved, but the flow rate control accuracy deteriorates due to insufficient time for pressure equalization and charging
Solution Approach 1:
The patent implements preliminary charging of the internal volume during the OFF interval before the short ON interval begins. The control mechanism ensures that gas is pre-charged to the required pressure level during the OFF period, so that when the short pulse occurs, the flow rate can be immediately and accurately controlled without waiting for pressure equalization during the pulse itself.
Solution Approach 2:
The patent uses real-time flow rate measurement and feedback control during the short pulse width operation. The flow sensor continuously monitors the actual flow rate, and the control mechanism dynamically adjusts the valve opening to maintain accurate flow rate control even during the brief ON interval, ensuring both high productivity and 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
This approach enhances the control accuracy of flow rates and pressures, enabling precise and consistent gas supply to deposition chambers, leading to high-quality film deposition with improved productivity and process efficiency.
Implementation Method 1
a pressure sensor that is arranged between the resistor and the first valve in the flow path and measures the pressure of the fluid in the internal volume between the resistor and the first valve
Implementation Method 2
a resistor arranged in a flow path through which fluid flows, wherein the resistor generates a flow path resistance in the flow path
Implementation Method 3
a feedback value calculator adapted to, on the basis of a pressure value measured by the pressure sensor, as a feedback value, calculate the time integrated value of a pressure drop occurring in the internal volume during an ON interval when the first valve is opened
Data Source
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AI summary
In order to provide a fluid control device capable of making the control accuracy of the flow rate or pressure of fluid passing through a valve during each ON interval of pulse control higher than before, the control mechanism includes: a pulse signal generator adapted to input a pulse signal having a predetermined pulse height and a predetermined pulse width to the first valve; a feedback value calculator adapted to, on the basis of a pressure value measured by a pressure sensor, as a feedback value, calculate the time integrated value of a pressure drop occurring in an internal volume during an ON interval when the first valve is opened; and a signal compensator adapted to, on the basis of the deviation between the feedback value and a reference value, compensate the pulse signal to be inputted from the pulse signal generator to the first valve.