Flow Rate Control Device Virtual Sensor Diagnosis
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Solution Overview
Problem
Existing flow rate control devices in semiconductor manufacturing require multiple sensors to diagnose clogging and abnormalities in measurement flow rates, leading to increased costs and complexity, while reducing the number of sensors complicates precise diagnosis.
Innovation Solution
A flow rate control device with a fluid resistor, a single pressure sensor, and calculating parts to estimate pressures and flow rates, allowing for accurate diagnosis of abnormalities using a reduced number of sensors, including a stable state judging part to ensure accurate calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to diagnose clogging and abnormalities in flow rate measurement, then diagnostic accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent creates a virtual copy of the downstream pressure sensor by calculating it from the upstream pressure measurement and the flow rate data. Instead of physically installing two pressure sensors, the system computes the downstream pressure value through mathematical relationships, thereby achieving dual-pressure monitoring capability while using only one physical sensor.
Solution Approach 2:
The patent introduces flow rate as an intermediary parameter that connects upstream pressure measurements to downstream pressure conditions. By using flow rate as a mediator, the system can infer downstream pressure from upstream pressure and flow rate relationships, eliminating the need for direct downstream pressure sensing.
2Reliability
If multiple sensors are installed to monitor flow rate accurately, then measurement reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent creates a virtual copy of the downstream pressure sensor by calculating it from the upstream pressure measurement and the flow rate data. Instead of physically installing two pressure sensors, the system computes the downstream pressure value through mathematical relationships, thereby achieving dual-pressure monitoring capability while using only one physical sensor.
Solution Approach 2:
The patent replaces the mechanical/physical sensing system with a computational approach. Instead of using physical sensors to directly measure downstream pressure, the system uses mathematical calculations based on upstream pressure and flow rate data to determine downstream pressure conditions, substituting physical measurement with computational derivation.
3Difficulty of detecting and measuring
If a thermal type flow rate sensor is added for diagnosis, then clogging detection capability is improved, but the number of parts and cost increase
Solution Approach 1:
The patent makes the existing flow rate measurement mechanism serve dual purposes: both for flow rate control feedback and for diagnostic purposes. By analyzing the relationship between upstream pressure, flow rate, and calculated downstream pressure, the system can detect clogging conditions without requiring separate diagnostic sensors, thereby achieving multi-functionality with existing components.
Solution Approach 2:
The patent creates a virtual copy of the downstream pressure sensor by calculating it from the upstream pressure measurement and the flow rate data. Instead of physically installing two pressure sensors, the system computes the downstream pressure value through mathematical relationships, thereby achieving dual-pressure monitoring capability while using only one physical sensor.
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
The solution enables accurate and cost-effective diagnosis of flow rate abnormalities with fewer sensors, maintaining high precision in flow rate control and reducing manufacturing costs by using a single pressure sensor and calculating parts to estimate pressures and flow rates.
Implementation Method 1
a first pressure sensor provided in a flow channel upstream of the fluid resistor; a second pressure sensor provided in the flow channel downstream of the fluid resistor
Implementation Method 2
a thermal type flow rate sensor for measuring a flow rate of fluid flowing through the flow channel
Data Source
AI summary
The flow rate control device is provided with: a fluid resistor provided on the flow channel; a pressure sensor provided in any one of an upstream side or a downstream side of the fluid resistor; a pressure calculating part configured to calculate a pressure in a side with respect to the fluid resistor where the pressure sensor is not provided; a flow rate calculating part configured to calculate a flow rate based on the measurement pressure value and a calculation pressure value calculated by the pressure calculating part; and an abnormality diagnosing part configured to diagnose an abnormality of the measurement flow rate value based on the measurement flow rate value and a calculation flow rate value.