Plasma Chamber Arcing Diagnosis Using Harmonic and Optical Sensing
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Solution Overview
Problem
Existing plasma etching processes face challenges in accurately detecting micro-arcing, which can cause significant damage to substrates and equipment due to the limitations of current sensors in detecting low-level arcing.
Innovation Solution
An apparatus and method utilizing a voltage-current (VI) sensor in a power filter connected to a heater or power supply line, combined with an optical sensor and a second VI sensor, to detect harmonics and light intensity, enabling accurate detection of arcing through an arcing detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If general sensors are used for arcing diagnosis, then the device complexity is low, but the measurement precision is insufficient to detect micro-arcing with low level
Solution Approach 1:
The patent divides the arcing detection system into multiple specialized sensors: a first VI sensor for detecting voltage and current harmonics from the heater power supply, a second VI sensor for detecting harmonics from the upper electrode power supply, and an optical sensor for detecting light intensity. Each sensor segment focuses on a specific aspect of arcing detection, enabling micro-arcing detection through coordinated analysis of multiple signal types rather than relying on a single general-purpose sensor.
Solution Approach 2:
The VI sensors are designed to detect multiple parameters simultaneously - both voltage and current harmonics - from different power supply lines (heater and upper electrode). The optical sensor detects light intensity variations. This multi-functional approach allows a single sensor type to monitor multiple aspects of the plasma process, improving detection precision without proportionally increasing system complexity.
2Reliability
If multiple sensors are deployed to detect micro-arcing, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent combines the detection functions of multiple sensors into a unified analysis system. The first VI sensor monitors the heater power supply line, the second VI sensor monitors the upper electrode power supply line, and the optical sensor monitors light intensity. These sensors are strategically positioned at different locations in the system, and their outputs are integrated to provide comprehensive arcing detection, improving reliability while managing complexity through coordinated sensor deployment.
Solution Approach 2:
The patent introduces an arcing detection algorithm that acts as an intermediary, analyzing the signals from multiple sensors and determining whether arcing occurs based on the combined information. This intermediary processing layer integrates the data from the first VI sensor, second VI sensor, and optical sensor, enabling reliable arcing detection without requiring direct complex interconnections between all sensors.
3Productivity
If RF power is applied for plasma etching, then the productivity is high, but arcing occurs in the process chamber causing damage
Solution Approach 1:
The patent implements a real-time feedback system where the first VI sensor, second VI sensor, and optical sensor continuously monitor the plasma process chamber during RF-powered plasma etching. The sensors detect harmonics and light intensity changes that indicate arcing conditions, and this information is fed back to control the etching process, enabling early detection and prevention of substrate damage while maintaining high productivity.
Solution Approach 2:
The patent applies preliminary anti-action by detecting early signs of arcing through harmonic analysis and light intensity monitoring before actual arcing damage occurs. The first VI sensor detects harmonics from the heater power supply, and the second VI sensor detects harmonics from the upper electrode power supply, allowing the system to take preventive action before arcing can damage the substrate, thus protecting against harmful effects while maintaining continuous high-productivity operation.
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
The solution allows for precise identification of both high and low-level arcing, preventing substrate and equipment damage by enabling real-time monitoring and control of plasma processing equipment.
Implementation Method 1
the first VI sensor configured to sense a harmonic generated from a first power supply that supplies alternating current power to the heater
Implementation Method 2
an optical sensor disposed on one side of the process chamber and configured to sense an intensity of light generated from the process chamber
Implementation Method 3
a second VI sensor disposed on a power supply line connected to an upper electrode of the process chamber, and configured to sense a harmonic generated from a second power supply supplying alternating current power to the upper electrode
Data Source
AI summary
An apparatus includes first and second VI sensors, an optical sensor, and an arcing detector. The first VI sensor is disposed in a power filter or on a power supply line connected to a heater disposed in a lower electrode of a process chamber in which a plasma process is performed. The first VI sensor senses a harmonic generated from a first power supply supplying power to the lower electrode and outputs a first signal. The optical sensor senses an intensity of light generated from the process chamber and outputs a second signal. The second VI sensor is disposed on a power supply line connected to an upper electrode and senses a harmonic generated from a second power supply supplying power to the upper electrode and outputs a third signal. The arcing detector determines whether arcing occurs based on one or more of the first, second, and third signals.