Mass Flow Controller Span Error Compensation by Pressure Decay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flow control systems in semiconductor manufacturing face challenges due to span errors in mass flow controllers, leading to inaccuracies in flow rate measurements, which affect process repeatability and require manual, time-consuming correction methods.
Innovation Solution
A flow control apparatus and method that automatically diagnoses and compensates for span errors in mass flow controllers using a system of valves, pressure sensors, and a controller to calculate compensation values based on flow rate decay and conversion coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual correction methods are used to correct measurement errors of a flow sensor, then the span error can be corrected, but the process is time-consuming and requires additional components and modification of existing components
Solution Approach 1:
The flow control system performs self-diagnosis and self-correction of span errors through automatic detection and compensation mechanisms. The controller automatically calculates compensation values based on discrepancies between set flow rates and actual flow rates, eliminating the need for manual intervention and reducing correction time while maintaining measurement precision.
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors the actual flow rate and compares it with the set flow rate. Based on this feedback, the controller automatically calculates and applies compensation values to correct span errors, enabling real-time correction without manual intervention and significantly reducing correction time.
2Measurement precision
If manual correction methods are used to correct measurement errors of a flow sensor, then the span error can be corrected, but additional components and modification of existing components are required
Solution Approach 1:
The controller is designed to perform multiple functions: it not only controls the flow controller but also automatically detects span errors, calculates compensation values, and applies corrections. This multi-functionality eliminates the need for separate correction devices and reduces system complexity while maintaining measurement precision.
Solution Approach 2:
The span error correction functionality is merged into the existing controller rather than being implemented as a separate system. The controller integrates detection, calculation, and correction functions, eliminating the need for additional components and reducing overall system complexity while achieving accurate flow rate measurement.
3Measurement precision
If manual correction methods are used to correct measurement errors of a flow sensor, then the span error can be corrected, but accurate measurement to obtain an accurate correction value is difficult
Solution Approach 1:
The controller uses feedback from the flow sensor to automatically detect span errors by comparing set flow rates with actual flow rates. This automated feedback mechanism eliminates the difficulty of manually detecting and measuring errors, ensuring accurate detection and correction of span errors without requiring complex manual measurement procedures.
Solution Approach 2:
The system replaces manual mechanical correction methods with an automated electronic control system. The controller automatically calculates compensation values based on electronic sensor data, eliminating the difficulty associated with manual measurement and correction while improving correction accuracy through precise electronic computation.
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
Accurately adjusts flow rate measurements by automatically correcting span errors, improving process repeatability and reducing the need for manual intervention.
Implementation Method 1
the controller is configured to sense a rate of decay of the fluid using the flow controller
Data Source
AI summary
There is provided a flow control apparatus and a flow control method that may diagnose and compensate for the span error of a mass flow controller to improve the accuracy. The flow control apparatus includes a first valve at an inlet of a fluid conduit, a second valve an outlet end of the fluid conduit, a flow controller which is disposed between the first valve and the second valve, and that includes a pressure sensor and a third valve, and a controller configured to control the first and second valves to be closed and the third valve to be open, sense a rate of decay of the pressure of the fluid using the mass flow controller, and to determine a span error of the flow controller using the rate of decay to derive a compensation value.