Substrate Liquid Flow Control Using Ultrasonic Error Feedback
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Solution Overview
Problem
Existing liquid supply systems for substrates in semiconductor manufacturing face challenges due to inaccurate flow rate measurement by measurement units, leading to flow rate hunting phenomena and process failures, which hinder precise liquid supply according to recipes.
Innovation Solution
A method and apparatus that utilize ultrasonic wave oscillation and reception to measure flow rates, identify errors, and implement feedback control modes (first and second) to adjust valve opening and closing rates based on error types, ensuring accurate liquid supply despite measurement inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a measurement unit is used to monitor liquid flow rate in real time, then the liquid supply can be adjusted according to the recipe, but measurement errors cause flow rate hunting and process failure
Solution Approach 1:
The patent implements feedback control by continuously monitoring the liquid flow rate through ultrasonic measurement and adjusting the valve opening/closing rate based on the measured flow rate to maintain the target flow rate. The controller receives the measured flow rate, compares it with the target flow rate from the recipe, and adjusts the valve to compensate for deviations, ensuring stable and accurate liquid supply despite disturbances or measurement variations.
Solution Approach 2:
The patent replaces traditional mechanical flow rate measurement devices with ultrasonic measurement technology. The ultrasonic sensor measures the flow rate by detecting the time of flight or frequency shift of ultrasonic waves traveling through the liquid, eliminating the need for mechanical components that may cause measurement errors or flow disturbances, thereby improving both measurement precision and process reliability.
2Ease of operation
If the valve opening and closing rate is adjusted based on measured flow rate, then the liquid supply can be controlled precisely, but measurement errors lead to incorrect flow rate control
Solution Approach 1:
The patent replaces mechanical flow rate measurement with ultrasonic measurement, providing more accurate and reliable flow rate data for the control system. This substitution eliminates errors associated with mechanical sensors, ensuring that the automatic control system receives accurate information for precise valve adjustment and maintains accurate liquid supply according to the recipe.
Solution Approach 2:
The system uses continuous feedback from ultrasonic flow rate measurement to adjust the valve opening/closing rate. The controller receives real-time flow rate data, compares it with the target flow rate from the recipe, and automatically adjusts the valve to maintain the correct flow rate, ensuring both ease of operation and manufacturing precision.
3Measurement precision
If ultrasonic wave oscillation is used to measure flow rate, then measurement accuracy can be improved, but the system complexity increases
Solution Approach 1:
The patent introduces an ultrasonic sensor as an intermediary device to measure flow rate non-invasively. The ultrasonic sensor transmits ultrasonic waves through the liquid and measures the flow rate based on the wave propagation characteristics, providing accurate measurement without direct contact with the liquid flow. This intermediary approach improves measurement precision while adding minimal complexity compared to mechanical measurement devices.
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
Ensures efficient substrate treatment by maintaining consistent liquid flow rates, preventing process failures, and adhering to treatment recipes even when measurement errors occur.
Implementation Method 1
a sensor that oscillates ultrasonic waves at one point inside the pipe and receives the ultrasonic waves at the other point inside the pipe
Implementation Method 2
measuring an arrival time of the ultrasonic waves from one point to the other to calculate a measurement flow rate
Data Source
AI summary
The present invention provides a method for treating a substrate. The method for treating a substrate comprises: a monitoring step of calculating a flow rate of a liquid, comparing the calculated measurement flow rate of the liquid with a set flow rate of the liquid in a normal state, and determining whether an error occurs in the measurement flow rate; and when an error is determined to occur in the measurement flow rate in the monitoring step, a feedback step of performing feedback control of a discharge flow rate of the liquid discharged to the substrate, wherein the feedback step determines a type of the error, and differently performs the feedback control according to the determined type of the error.