Calibration Circuit for Semiconductor Gas Flow Measurement
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Solution Overview
Problem
Conventional gas delivery systems in semiconductor processing chambers lack accuracy in measuring gas flows, which affects substrate temperature control and processing results due to variations in temperature and pressure, leading to processing defects and inefficient gas usage.
Innovation Solution
A calibration circuit with a gas source, diverter valve, orifice, and sensing circuit is used to verify and calibrate gas flows, employing a calibrated or non-calibrated volume and sensors to measure flow rate and pressure, simulating processing chamber conditions without actual flow into the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mass flow controllers are used for gas flow control, then the system is simple to operate, but the measurement precision deteriorates due to temperature, pressure and volume variations
Solution Approach 1:
The patent introduces a calibration circuit as an intermediary device between the mass flow controller and the processing chamber. This calibration circuit includes a calibrated volume and sensing circuit that measures actual gas flow by detecting pressure changes in the calibrated volume, thereby providing accurate flow measurement without requiring complex direct measurement systems in the processing chamber.
Solution Approach 2:
The patent implements a feedback mechanism where the sensing circuit continuously monitors the actual gas flow through the calibration circuit and provides this information back to the control system. This feedback loop enables the system to compensate for temperature, pressure and volume variations, maintaining measurement precision despite changing operating conditions.
2Manufacturing precision
If gas flow is not accurately controlled, then the system is easier to operate, but manufacturing precision deteriorates causing processing defects
Solution Approach 1:
The calibration circuit is designed to automatically verify and calibrate gas flow without requiring manual intervention or complex user configuration. The system self-calibrates by using the known calibrated volume and sensing circuit to determine actual flow rates, making the high-precision measurement system as easy to operate as conventional systems while ensuring manufacturing precision.
3Loss of substance
If conventional flow measurement is used, then the device complexity is low, but loss of substance increases due to inefficient gas usage
Solution Approach 1:
The patent replaces conventional mechanical flow measurement methods with an electronic sensing system that uses pressure detection in a calibrated volume to determine gas flow rates. This substitution enables more precise measurement and control of gas flow, reducing waste of costly gases while maintaining acceptable system complexity through the use of standard electronic components.
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 solution enhances the accuracy and confidence of gas delivery in semiconductor processing systems, improving substrate temperature control and reducing processing defects and gas wastage, enabling more precise control of gas flows for next-generation circuit designs.
Implementation Method 1
The orifice is fluidly coupled to a first outlet of the diverter valve and has substantially the same flow resistance as a processing chamber
Implementation Method 2
a sensor configured to detect at least one of electrical or magnetic characteristics of gases disposed in the calibrated volume
Data Source
AI summary
A method and apparatus for measuring gas flow are provided. In one embodiment, a calibration circuit for gas control may be utilized to verify and/or calibrate gas flows utilized for backside cooling, process gas delivery, purge gas delivery, cleaning agent delivery, carrier gases delivery and remediation gas delivery, among others.