Plasma Inspection via Reflected Wave Monitoring
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Solution Overview
Problem
Plasma processing in plasma processing apparatuses often results in substrate damage and contamination due to unstable plasma ignition, which existing methods fail to adequately address.
Innovation Solution
An inspection method that monitors the power of reflected waves, specifically radio frequency or microwave waves, to determine the fluctuation in peak-to-peak voltage or impedance at the lower electrode, allowing for the assessment of plasma sheath fluctuations and subsequent contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma ignition is performed in the plasma processing apparatus, then substrate processing can be carried out, but substrate damage and contamination occur due to unstable plasma ignition
Solution Approach 1:
The system performs preliminary monitoring of reflected wave power before substrate processing to detect plasma ignition stability. By observing the reflected wave characteristics during the plasma ignition phase, the system can identify unstable ignition conditions before they cause substrate damage, allowing preventive actions to be taken.
Solution Approach 2:
The system continuously monitors the reflected wave power from the plasma generation process and uses this feedback information to assess plasma ignition stability. The control unit analyzes the reflected wave characteristics in real-time to determine whether plasma ignition is stable, providing continuous feedback on the plasma generation process quality.
2Measurement precision
If reflected wave power is monitored to detect plasma ignition stability, then substrate contamination can be detected, but the system complexity increases
Solution Approach 1:
The system uses the reflected wave as an intermediary parameter to indirectly measure plasma ignition stability and substrate contamination risk. Instead of directly measuring substrate contamination, the system monitors the reflected wave power from the plasma generation process, which serves as a mediator that correlates with plasma stability and potential contamination.
Solution Approach 2:
The system replaces direct physical inspection methods with electromagnetic wave-based monitoring. By using radio frequency or microwave reflections to detect plasma ignition stability, the system substitutes complex mechanical or direct sampling measurement systems with a non-contact, electromagnetic field-based detection approach.
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
Enables the detection of substrate contamination by measuring fluctuations in the plasma sheath, thereby preventing damage and contamination by determining if the fluctuation meets allowable conditions, ensuring stable plasma processing.
Implementation Method 1
a source power supply configured to supply a power wave for generation of plasma from gas in the chamber to the gas in the chamber
Implementation Method 2
a matching unit configured to adjust an output impedance of the source power supply to an input impedance of the chamber
Data Source
AI summary
An inspection method is provided. The inspection method includes monitoring power of a reflected wave of a power wave supplied from a source power supply for generation of plasma in a plasma processing apparatus, and obtaining a fluctuation amount of a measured value within a period after initiation of the supply of the power wave. The fluctuation amount of the measured value is a fluctuation amount indicating a fluctuation in a peak-to-peak voltage at a lower electrode of the substrate support in the chamber or a fluctuation amount indicating a fluctuation in impedance of a load including the lower electrode.