Plasma Potential Sensing for Adaptive Abnormal Discharge Detection
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Solution Overview
Problem
Conventional plasma processing apparatuses fail to accurately detect abnormal discharges due to fixed voltage thresholds that do not account for varying plasma processing conditions, leading to potential misjudgments.
Innovation Solution
A plasma processing apparatus and method that dynamically determines a threshold for abnormal discharge detection based on specific plasma processing conditions, including high-frequency power, pressure, gas composition, and substrate information, using a threshold determination section to set appropriate thresholds for each condition, thereby enhancing the accuracy of abnormal discharge judgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed voltage threshold is used for abnormal discharge detection, then the detection mechanism is simple, but the detection accuracy deteriorates because the threshold cannot adapt to varying plasma processing conditions
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed voltage threshold to a dynamic threshold that automatically adjusts according to plasma processing conditions. The threshold determination section calculates appropriate thresholds based on real-time parameters such as gas flow rates, pressure, and power, enabling the detection system to adapt to varying operating conditions and maintain high detection accuracy without manual intervention.
Solution Approach 2:
The patent implements parameter changes by using the threshold determination section to modify the voltage threshold parameter based on changes in plasma processing parameters. When processing conditions such as gas flow rate, pressure, or power change, the system automatically recalculates and updates the threshold to reflect the new operating state, ensuring accurate abnormal discharge detection across different processing scenarios.
2Reliability
If a fixed voltage threshold is used, then the system operation is simple, but false detection occurs when the voltage exceeds the threshold under normal varying plasma conditions
Solution Approach 1:
The patent applies the self-service principle through the threshold determination section, which automatically determines appropriate voltage thresholds without requiring manual intervention or complex operator judgment. The system self-adjusts the threshold based on measured plasma processing parameters, eliminating the need for operators to manually calibrate thresholds for different processing conditions while maintaining high detection reliability.
Solution Approach 2:
The patent implements feedback by using the threshold determination section to continuously monitor plasma processing parameters and adjust the voltage threshold accordingly. The system measures actual processing conditions, compares them with reference values, and feeds back the appropriate threshold setting to the detection mechanism, creating a closed-loop system that maintains high reliability across varying operating conditions.
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 allows for precise detection of abnormal discharges by adapting the threshold to the current plasma processing conditions, reducing false positives and negatives, and ensuring reliable plasma processing operations.
Implementation Method 1
an electrode part configured to be applied with a high-frequency power for generating a plasma in the chamber
Implementation Method 2
a plasma sensor for measuring a measured value corresponding to an electric potential of the plasma
Data Source
AI summary
Disclosed is a plasma processing apparatus 100 including: a chamber 101 in which plasma processing is performed; an electrode part 105 configured to be applied with a high-frequency power for generating a plasma in the chamber 101; a plasma sensor 160 for measuring a measured value MV corresponding to an electric potential of the plasma; a threshold determination section 122 for determining a threshold TH, depending on a plasma processing condition; and a judgment section 123 for judging presence or absence of abnormal discharge in the chamber 101, based on the measured value MV and the threshold TH.