Self-Calibrating Flow Rate Sensor Mechanism
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Solution Overview
Problem
Existing flow rate sensors in semiconductor processes face calibration challenges due to errors caused by contamination and other factors, leading to inaccurate measurements, and current diagnostic mechanisms cannot perform self-calibration without a reference sensor, resulting in maintenance downtime and reduced accuracy.
Innovation Solution
A self-calibrating mechanism that calculates a calibration factor using the diagnostic volume from the integrated flow rate value, allowing for self-calibration of the flow rate sensor without a reference sensor, and a diagnostic mechanism that divides the fluid parameter changing interval into multiple intervals to quantify errors and perform precise calibration for each interval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional diagnostic mechanism is used to verify flow rate sensor accuracy, then abnormality can be detected, but self-calibration cannot be performed and maintenance downtime occurs
Solution Approach 1:
The flow rate sensor performs self-calibration using its own measured values and the diagnostic mechanism. The sensor calculates calibration factors based on integrated flow rate values during valve transitions, enabling it to self-correct measurement errors without external reference sensors or manual intervention, thus eliminating maintenance downtime while maintaining measurement precision
Solution Approach 2:
The diagnostic mechanism continuously monitors the relationship between measured flow rate values and actual fluid behavior. By calculating calibration factors from integrated flow rate data and feeding this information back to adjust future measurements, the system maintains accuracy over extended periods without requiring external calibration references
2Measurement precision
If a reference flow rate sensor is used for calibration, then measurement accuracy can be maintained, but device complexity and cost increase
Solution Approach 1:
The invention extracts the calibration function from a separate reference sensor and implements it within the existing flow rate sensor using its own measured values. By removing the need for additional reference sensors and simplifying the calibration approach to use only integrated flow rate data from the sensor itself, the system maintains measurement precision while reducing device complexity and cost
Solution Approach 2:
The flow rate sensor is designed to perform multiple functions: normal flow rate measurement, self-diagnosis of measurement accuracy, and self-calibration. By integrating these functions into a single sensor system rather than requiring separate reference sensors for calibration, the system achieves measurement precision without increasing device complexity
3Measurement precision
If the fluid parameter changing interval is measured collectively, then overall accuracy can be verified, but specific interval errors cannot be identified for targeted calibration
Solution Approach 1:
The diagnostic mechanism divides the fluid parameter changing interval into multiple discrete intervals and calculates integrated flow rate values for each segment. This segmentation enables identification of which specific intervals contain measurement errors, allowing targeted calibration adjustments rather than applying uniform corrections across the entire measurement range, thus preserving interval-specific error information while maintaining overall accuracy
Data Source
AI summary
A valve fully closing part; a calibrating volume calculation part that calculates a calibrating volume on the basis value of an integration of a flow rate measured value outputted from a flow rate sensor in a fluid parameter changing interval; and a calibration part that calibrates a flow rate on the basis of the calculated calibrating volume and a preset reference volume are provided.