Gas Flow Measurement Using Pressure Timing Correction
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Solution Overview
Problem
In substrate processing, achieving high accuracy in gas flow measurement is challenging due to timing delays in control systems, which can lead to significant deviations in measurement results and deteriorate correction accuracy, especially in atomic layer etching processes.
Innovation Solution
A method and apparatus for measuring gas flow that involves measuring pressures and temperatures in multiple flow paths, calculating gas flow based on these parameters, and correcting for timing delays by averaging gas supply times and using theoretical gas supply times to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas flow is measured using conventional methods in substrate processing, then the measurement can be performed, but the measurement accuracy deteriorates due to timing delays in control systems
Solution Approach 1:
The patent applies feedback by measuring the actual gas supply time using a timer that starts when the gas supply instruction is issued and stops when the gas supply is completed, then using this measured time to correct the theoretical gas flow calculation. This closed-loop feedback mechanism compensates for timing delays in the control system, improving measurement accuracy without requiring faster hardware.
Solution Approach 2:
The patent changes the parameter from theoretical gas supply time (specified in the controller) to actual measured gas supply time. By measuring the real-time duration of gas supply and using this corrected time parameter in the gas flow calculation, the system accounts for timing delays and improves measurement precision.
2Manufacturing precision
If the gas supply time is not corrected for timing delays, then the measurement process is simple, but the correction accuracy deteriorates
Solution Approach 1:
The system performs self-correction by automatically measuring its own timing delays and using this information to correct the gas flow calculation. The timer and controller work together to autonomously identify and compensate for timing errors, improving correction accuracy without requiring external calibration equipment or complex manual adjustment procedures.
3Measurement precision
If multiple pressure and temperature measurements are performed, then the gas flow calculation accuracy is improved, but the measurement time increases
Solution Approach 1:
The patent performs preliminary measurements of pressure and temperature in the flow paths before calculating the gas flow. By having these measurements ready in advance and using the corrected gas supply time together with these pre-obtained parameters, the system achieves accurate gas flow calculation without requiring repeated measurements during the actual gas supply process.
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
This approach enables high-accuracy gas flow measurement and correction, enhancing the reproducibility and precision of gas flow control, thereby improving the substrate processing outcomes.
Implementation Method 1
measuring a first pressure of a gas filled in a first flow path connected to a flow controller and a second flow path connected to the first flow path
Implementation Method 2
measuring a second pressure and a temperature of the gas filled in the first flow path and the second flow path after the gas is supplied
Data Source
AI summary
A gas flow measuring method is provided. A first pressure of a gas in a first and a second flow path is measured. A gas is supplied to the first and the second flow paths by repeating gas supply and stop of the gas supply, and a gas supply time is measured. A second pressure and a temperature of the gas in the first and the second flow path is measured, a third pressure of the gas in the second flow path is measured after the gas is exhausted from the second flow path, and a fourth pressure of the gas in the first and the second flow path is measured. The gas flow supplied to the first and the second flow path is calculated based on the first to fourth pressures and the temperature, and corrected based on a theoretical gas supply time and a calculated average time.