OES Sensor Leak Detection in Plasma Processing Chambers
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Solution Overview
Problem
Existing semiconductor manufacturing equipment faces challenges in detecting small leaks and virtual leaks in processing chambers, which can adversely affect wafer processing due to their subtlety and impact on gas composition.
Innovation Solution
An optical emission spectroscopy (OES) sensor is used to monitor the plasma in the chamber, detecting leaks by analyzing the optical spectrum of the gas or its reaction products, with a processor computing a leak detection index to identify and notify potential leaks, applicable to chambers at various pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional leak detection methods are used, then large leaks can be detected, but small leaks and virtual leaks cannot be detected
Solution Approach 1:
The patent replaces traditional mechanical or pressure-based leak detection methods with optical emission spectroscopy (OES). The OES sensor detects leaked gases by analyzing their optical emission spectra when exposed to plasma, enabling detection of small leaks and virtual leaks that were previously undetectable by conventional means.
Solution Approach 2:
The patent changes the detection parameter from pressure or flow rate to optical emission spectrum characteristics. By monitoring specific spectral lines and their intensities, the system can identify the presence and concentration of leaked gases with high sensitivity, resolving the contradiction between detection precision and process reliability.
2Measurement precision
If OES sensor is used to detect small leaks, then detection sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent leverages the existing OES sensor already present in the plasma processing chamber for its primary plasma monitoring function and repurposes it for leak detection as well. This multi-functional use of the OES sensor avoids adding separate dedicated leak detection equipment, thereby minimizing the increase in device complexity while maintaining high detection sensitivity.
Solution Approach 2:
The system uses the plasma environment already present in the chamber for leak detection purposes. The leaked gases are ionized by the existing plasma, and their optical emission spectra are captured by the OES sensor without requiring additional excitation sources or complex sample introduction systems, thus keeping the system relatively simple.
3Speed
If real-time spectrum analysis is performed, then leak detection speed is improved, but processing time increases
Solution Approach 1:
The patent pre-processes the spectral data by identifying and monitoring specific characteristic wavelengths or spectral regions associated with potential leaked gases. By focusing analysis on these predetermined spectral features rather than processing the entire spectrum, the system achieves rapid leak detection with minimal processing time.
Solution Approach 2:
The system performs partial spectrum analysis by concentrating on specific spectral lines or regions of interest rather than analyzing the complete spectrum. This selective approach provides sufficient leak detection capability while significantly reducing the computational burden and processing time.
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
Effectively detects small and virtual leaks, ensuring reliable processing by identifying gas composition changes and alerting operators, thereby preventing damage to wafers.
Implementation Method 1
an optical emission spectroscopy (OES) sensor configured to monitor light emitted from plasma of a sample of gas from the chamber
Implementation Method 2
monitor light emitted from plasma of a sample of gas from the chamber
Data Source
AI summary
Leaks in a processing chamber, including “virtual leaks” resulting from outgassing of material present within the chamber, may be detected utilizing an optical emission spectroscopy (OES) sensor configured to monitor light emitted from plasma of a sample from the chamber. According to certain embodiments, gas introduced into the chamber by the leak may be detected directly on the basis of its optical spectrum. Alternatively, gas introduced by the leak may be detected indirectly, based upon an optical spectrum of a material resulting from reaction of the gas attributable to the leak. According to one embodiment, data from the OES sensor is received by a processor that is configured to compute a leak detection index. The value of the leak detection index is compared against a threshold to determine if a leak is detected. If the value of the index crosses the threshold, a notification of the existence of a leak is sent.