Flow Rate Control with In-Process Abnormality Diagnosis
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Solution Overview
Problem
Conventional flow control devices in semiconductor manufacturing require stopping the manufacturing process to perform self-diagnosis, leading to intermittent condition monitoring and reduced throughput due to the need to fully close the flow path for diagnostic purposes.
Innovation Solution
A flow control device with a fluid resistor, downstream valve, resistance flow rate measurement mechanism, inflow/outflow flow rate calculation unit, valve flow rate estimation unit, flow rate control unit, diagnostic parameter calculation unit, and diagnostic unit that allows for abnormality diagnosis while maintaining a set flow rate, enabling continuous operation and improved diagnostic accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flow path is fully closed to perform self-diagnosis, then diagnostic accuracy is improved, but manufacturing process continuity deteriorates
Solution Approach 1:
The patent enables continuous flow rate supply to the chamber during diagnostic operations by using a dual-valve configuration. The first valve (upstream) can be closed to isolate the reference volume for diagnosis, while the second valve (downstream) remains open to maintain continuous flow rate supply to the chamber. This allows diagnostic measurements to be performed without interrupting the manufacturing process, thus maintaining continuity of useful action.
2Reliability
If the flow path is fully closed for self-diagnosis, then sensor abnormality detection is improved, but process throughput deteriorates
Solution Approach 1:
The patent divides the flow control system into two separate controllable segments using two valves: a first valve positioned upstream of the reference volume and a second valve positioned downstream. This segmentation allows independent control of each section - the upstream section can be isolated for sensor diagnosis while the downstream section continues to supply flow rate to the chamber, thereby maintaining process throughput during diagnostic operations.
3Ease of operation
If self-diagnosis is performed during maintenance stops, then sensor condition monitoring is simplified, but manufacturing throughput deteriorates
Solution Approach 1:
The patent enables diagnostic operations to be performed continuously during normal manufacturing operations rather than requiring scheduled maintenance stops. By using the first valve to isolate the reference volume while maintaining flow rate supply through the second valve, the system can perform sensor condition monitoring without stopping the manufacturing process, thus maintaining high throughput while providing continuous monitoring capability.
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 concurrent abnormality diagnosis and stable flow rate supply, eliminating the need for process interruptions and improving diagnostic accuracy by calculating diagnostic parameters based on resistance and inflow/outflow flow rates during normal operation.
Implementation Method 1
a fluid resistor R provided in a flow path
Implementation Method 2
a pressure change state of an increasing or decreasing of an upstream side pressure
Data Source
AI summary
Provided is a flow rate control device capable of diagnosing whether an abnormality has occurred while continuing to supply a predetermined flow rate. The flow rate control device calculates an inflow/outflow rate of a fluid into a volume on the basis of a downstream pressure that is the pressure in the volume; estimates a valve flow rate that is a flow rate of the fluid that flows out of the volume through the downstream valve on the basis of the resistance flow rate and the inflow/outflow flow rate; controls the downstream valve so that the difference between the set flow rate and the valve flow rate decreases; calculates a diagnostic parameter on the basis of the resistance flow rate or the inflow/outflow flow rate in a pressure change state in which the upstream side pressure increases or decreases; and diagnoses an abnormality based on the diagnostic parameter.