Self-Validating Mass Flow Controller In-Situ Decay Measurement
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Solution Overview
Problem
Mass flow controllers (MFCs) in industrial processes face issues with performance drift and clogging, leading to reduced repeatability and yield, requiring offline Rate of Decay (ROD) measurements that disrupt production and are not performed frequently due to downtime concerns.
Innovation Solution
A self-validating mass flow controller system that performs in-situ ROD measurements using a software protocol, eliminating the need for a separate device and avoiding hardware changes, allowing real-time monitoring without stopping the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offline ROD measurements are performed to detect performance drift, then measurement precision is improved, but productivity deteriorates due to production downtime
Solution Approach 1:
The patent replaces the mechanical interruption of gas supply required for offline ROD measurements with a software-based control method. The MFC controller software initiates and manages the ROD measurement sequence, using electronic control signals to close the control valve and trigger the pressure decay measurement, eliminating the need for physical production interruption while maintaining measurement accuracy
Solution Approach 2:
The patent enables continuous operation of the semiconductor manufacturing tool by performing ROD measurements during normally idle periods or transitions in the manufacturing process. The measurement is integrated into the existing process flow rather than requiring separate production stoppage, allowing the tool to maintain continuous wafer processing while periodically verifying MFC performance
2Reliability
If frequent offline ROD measurements are performed, then reliability is improved through timely detection of performance drift, but loss of time increases due to repeated production interruptions
Solution Approach 1:
The patent replaces the mechanical system that required production stoppage for measurements with a software-controlled measurement sequence that executes during normal operation. The controller software manages the measurement timing, valve actuation, and data collection electronically, allowing frequent verification without cumulative production loss
Solution Approach 2:
The patent performs ROD measurements proactively during scheduled maintenance windows or between production batches, before performance drift can significantly impact yield. The software system automatically schedules and executes measurements at predetermined intervals, preventing rather than merely detecting performance issues
3Measurement precision
If a separate device is installed to perform ROD measurements, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the ROD measurement functionality into the existing MFC controller by integrating the measurement software module with the valve control and pressure sensing capabilities already present in the device. This consolidation eliminates the need for separate measurement equipment while maintaining measurement precision through utilization of existing high-quality components
Solution Approach 2:
The patent enables the MFC controller to perform multiple functions: normal flow control during production and ROD measurement verification during idle periods. The same hardware components (valve, pressure sensor, processor) are utilized for both production operation and performance verification, eliminating the need for dedicated measurement equipment
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 continuous, real-time monitoring and validation of MFC performance, reducing downtime and maintaining process reliability by identifying valve leaks and flow measurements during online operation.
Implementation Method 1
a mass flow sensor for providing a signal corresponding to mass flow of the fluid through the flow path
Implementation Method 2
Starting a ROD measurement is done by interrupting the gas supply upstream of the pressure sensor and letting the pressure decay
Implementation Method 3
a software protocol configured to execute, in-situ, a rate of decay measurement
Data Source
AI summary
The disclosed embodiments include a method, apparatus, and computer program product for verifying a performance of a mass flow controller or mass flow meter on a tool. For example, the disclosed embodiments include a method and a mass flow controller configured to perform, in-situ, by the mass flow controller, a rate of decay measurement during on-line operation of the tool to identify valve leak issues and/or for performing a flow measurement.