Substrate Gas Flow Control for Rapid ALD and ALE Pulse Cycles
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Solution Overview
Problem
In semiconductor manufacturing, particularly in atomic layer etching processes, the existing flow rate controllers fail to accurately control gas flow rates due to poor reproducibility and responsiveness during rapid ON and OFF cycles, leading to communication errors and reduced yield.
Innovation Solution
A method that involves setting a threshold pressure value in a flow rate controller, measuring and normalizing the gas pressure, and calculating the total flow rate based on the elapsed time, allowing for precise monitoring and elimination of individual differences in flow rate controllers, thereby ensuring accurate gas flow rate control even during short ON and OFF cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a flow rate controller is used to control gas flow rate in rapid ON and OFF cycles, then gas flow rate control is achieved, but reproducibility and accuracy deteriorate due to poor responsiveness
Solution Approach 1:
The patent implements feedback control by continuously monitoring the integrated value of the pressure differential across the flow rate controller and comparing it against a target integrated value. The flow rate controller adjusts the gas flow rate based on the difference between the actual and target integrated values, ensuring accurate control even during rapid ON and OFF cycles. This feedback mechanism eliminates the reproducibility issues inherent in open-loop control systems.
Solution Approach 2:
The patent replaces direct mechanical flow rate measurement and control with a pressure differential integration approach. Instead of relying on mechanical flow sensors that struggle with rapid changes, the system uses pressure sensors to measure the pressure differential across the flow rate controller and integrates this signal over time to determine the cumulative gas flow. This substitution of measurement methodology improves responsiveness and reproducibility.
2Productivity
If conventional flow rate control methods are used, then gas supply is achieved, but measurement precision deteriorates due to inability to accurately measure total flow rate during short cycles
Solution Approach 1:
The patent replaces conventional flow rate measurement methods with pressure differential integration. By measuring the pressure differential across the flow rate controller and integrating this signal over the entire cycle time, the system accurately determines the total gas flow rate supplied during short ON and OFF cycles. This method overcomes the limitations of conventional flow sensors that cannot accurately measure flow during rapid transitions.
Solution Approach 2:
The patent performs preliminary calibration by establishing the relationship between the pressure differential signal and the actual gas flow rate before production cycles. The integration constant and scaling factors are determined in advance through calibration procedures, allowing the system to accurately calculate total flow rate during subsequent rapid cycles without requiring complex real-time computations.
3Device complexity
If individual differences in flow rate controllers are not compensated, then device complexity is reduced, but manufacturing precision deteriorates due to variability in controller performance
Solution Approach 1:
The feedback control loop automatically compensates for individual differences in flow rate controllers by continuously adjusting the control signal based on the actual performance of each specific controller. The system learns the characteristics of each controller through the integration process and adjusts accordingly, eliminating the need for manual calibration or complex compensation algorithms while maintaining manufacturing precision.
Solution Approach 2:
The flow rate controller system performs self-calibration and self-compensation through the integration-based control method. Each controller automatically adapts to its own characteristics during the calibration phase, and the feedback mechanism ensures that individual variations are compensated during operation. This self-service approach maintains manufacturing precision without increasing device complexity.
Data Source
AI summary
A substrate processing method of processing a substrate using a gas supplied to a chamber includes: (a) setting a threshold value of a pressure of the gas, which is a control target in a flow rate controller configured to measure the pressure of the gas supplied to the chamber and control a flow rate of the gas; (b) supplying the gas into the chamber; (c) measuring the pressure of the gas by the flow rate controller; (d) stopping the supply of the gas into of the chamber; (e) calculating a time when the pressure of the gas measured in (c) becomes equal to or higher than the threshold value; and (f) calculating a total flow rate of the gas supplied into the chamber based on the pressure of the gas measured in (c) and the time calculated in (e).