Mass Flow Controller Zero-Point Calibration Using Pressure Stability
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Solution Overview
Problem
Mass flow control devices in semiconductor manufacturing face challenges in accurately measuring and controlling gas flowrates, leading to inconsistencies in processing quality due to inadequate zero point calibration methods.
Innovation Solution
A method and device configuration that involves closing valves to prevent fluid flow, using pressure and flowrate sensors to determine fluid stability, calculating a zero point calibration value based on temperature and flowrate measurements, and applying this value to the flowrate sensor to maintain accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual zero point calibration is performed, then measurement accuracy can be adjusted, but manpower consumption and processing time increase
Solution Approach 1:
The mass flow control device performs automatic zero point calibration using its own integrated sensors (flowrate sensor, temperature sensor, pressure sensor) and controller. The system self-determines fluid stability, self-calculates the zero point calibration value, and self-applies the calibration without external manual intervention, thereby reducing manpower consumption while maintaining measurement accuracy
Solution Approach 2:
The system performs preliminary checks of fluid stability using flowrate and pressure sensors before conducting zero point calibration. By pre-verifying that the fluid is stable and the system is in the correct state, the calibration process can proceed automatically without requiring manual verification steps, reducing overall processing time
2Measurement precision
If comprehensive calibration checks are performed, then calibration accuracy improves, but device complexity increases
Solution Approach 1:
The controller serves multiple functions: it controls the main valve, monitors flowrate via the flowrate sensor, measures temperature via the temperature sensor, measures pressure via the pressure sensor, determines fluid stability, calculates the zero point calibration value, and applies the calibration. By making the controller multi-functional, the system achieves comprehensive calibration checks without adding separate dedicated components for each function
Solution Approach 2:
The patent combines multiple calibration-related components (flowrate sensor, temperature sensor, pressure sensor, controller) into an integrated calibration system where the controller centrally manages all calibration operations. This merging approach allows comprehensive checks to be performed through coordinated use of existing components rather than requiring separate complex subsystems
3Productivity
If automatic calibration is implemented, then productivity improves, but measurement precision may be compromised
Solution Approach 1:
The system continuously monitors flowrate, temperature, and pressure during the calibration process using integrated sensors. The controller uses this real-time feedback to determine fluid stability and automatically adjust the calibration process, ensuring that zero point calibration is only applied when the system is in the correct state. This feedback mechanism maintains measurement precision while enabling automatic operation
Solution Approach 2:
Before performing automatic zero point calibration, the system preliminarily checks whether the fluid is stable by monitoring flowrate and pressure values. This preliminary verification ensures that automatic calibration is only conducted under appropriate conditions, maintaining measurement accuracy while improving calibration efficiency through automation
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 ensures precise control of gas flowrates, improves processing quality, and automates the zero point calibration process, reducing manpower and processing time.
Implementation Method 1
a flowrate sensor provided on a sensor flow path extending between the inflow path and the outflow path
Data Source
AI summary
A method of calibrating a zero point of a mass flow control device includes closing a valve installed in a main flow path of the mass flow control device to block the main flow path and prevent a fluid from flowing in the main flow path, determining, based on a pressure value measured using a pressure meter installed in the main flow path, whether the fluid has stopped flowing, determining, based on a flowrate value measured by a flowrate sensor provided on a sensor flow path connected to the main flow path, whether the fluid is stable, calculating a zero point calibration value based on a temperature value of the fluid measured by a thermometer installed in the main flow path and the flowrate value measured by the flowrate sensor, and applying the zero point calibration value to a zero point of the flowrate sensor.