Plasma Chamber RF Power Control via Waveform Distortion Detection
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Solution Overview
Problem
Current methods for controlling plasma chambers in semiconductor manufacturing are inadequate in preventing and mitigating electrical arcing, which can cause damage due to slow detection and failure to capture fast transients.
Innovation Solution
A system and method that includes an RF generator, a sensor to measure parameters at the plasma chamber input, and a control unit to detect excessive and repetitive changes in these parameters, allowing for timely reduction of RF power to prevent arcing, comprising a processor to analyze voltage, current, and phase angle signals to determine and respond to arcing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional arc detection methods are used, then arc detection capability is provided, but detection speed is slow and fast transients are not captured
Solution Approach 1:
The patent replaces conventional slow arc detection methods with a new detection system that monitors voltage and current waveforms in real-time. The system calculates the difference between measured waveforms and reference waveforms to detect arcs based on waveform distortion rather than relying on slow threshold-based methods. This substitution enables capture of fast transients and significantly improves detection speed while maintaining reliability.
2Object-affected harmful factors
If RF power is reduced to prevent arcing, then arcing damage is prevented, but plasma processing efficiency decreases
Solution Approach 1:
The system performs preliminary detection of arc conditions by continuously monitoring waveform differences before actual arcing occurs. When arc conditions are detected through waveform distortion analysis, the system can take preventive action by adjusting RF power or other parameters in advance, preventing arc damage while maintaining normal plasma processing conditions and efficiency throughout most of the operation cycle.
Solution Approach 2:
The patent implements a feedback control system that continuously compares measured voltage and current waveforms against reference waveforms. When deviations indicating arc conditions are detected, the system provides feedback to adjust RF power or other processing parameters. This closed-loop feedback enables dynamic prevention of arcing while maintaining optimal plasma processing conditions, resolving the contradiction between damage prevention and processing efficiency.
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 prevents arcing and reduces damage by rapidly detecting excessive and repetitive changes in plasma chamber conditions, ensuring efficient and reliable plasma processing.
Implementation Method 1
a sensor component configured to measure a parameter at the chamber input; and a control unit configured to receive a sensor signal from the sensor component, the sensor signal indicative of the measured parameter
Implementation Method 2
Plasma processing involves energizing a gas mixture by imparting energy to the gas molecules by introducing radio frequency (RF) energy into the gas mixture. This gas mixture is typically contained in a vacuum plasma chamber, and the RF energy is typically introduced into the plasma chamber through electrodes
Implementation Method 3
determine a rate of change based on the measured parameter; detect an excessive rate of change condition comprising the rate of change exceeding a reference rate of change
Data Source
AI summary
An system and method for controlling a plasma chamber includes operably coupling an RF generator to the plasma chamber, the RF generator providing an RF signal to a chamber input of the plasma chamber; measuring a parameter at the chamber input; determining a rate of change based on the measured parameter; detecting an excessive rate of change condition comprising the rate of change exceeding a reference rate of change; detecting a repetitive change condition comprising a predetermined number of the excessive rate of change conditions in a predetermined time; upon detection of the repetitive change condition, decreasing a power of the RF signal provided to the chamber input.