Inductive RF Voltage Detection in Plasma Processing
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in reliably maintaining RF voltage supplied to substrate supporting members due to waveform distortion caused by noise frequencies, making precise detection of inductive RF voltage difficult.
Innovation Solution
The apparatus employs a matching device with an inductive RF detecting unit and filter to remove noise frequencies, using inductors and capacitors to isolate the desired frequency, allowing for precise detection and control of the inductive RF voltage, and an inductive D.C. voltage detecting unit to remove A.C. elements, ensuring reliable RF voltage maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a RF voltage is supplied to a substrate supporting member for plasma processing, then plasma generation is achieved, but waveform distortion occurs due to noise frequencies making precise detection difficult
Solution Approach 1:
The patent extracts the useful RF signal from the noisy environment by using a band-pass filter to isolate the fundamental RF frequency component. The filter removes noise frequencies (harmonics and interference) from the detected voltage waveform, allowing precise measurement of only the relevant plasma-generating RF component.
Solution Approach 2:
The patent introduces an intermediary detection system consisting of a voltage probe, amplifier, and band-pass filter between the substrate supporting member and the measurement device. This intermediary system conditions the raw signal by amplifying it and filtering out noise frequencies, enabling accurate detection of the RF voltage without directly measuring the distorted waveform at the substrate.
2Productivity
If noise frequencies are present in the RF voltage waveform, then plasma processing can proceed, but the RF peak-to-peak voltage detection becomes unreliable due to waveform distortion
Solution Approach 1:
The patent implements a feedback control system where the detected and filtered RF voltage information is used to monitor and adjust plasma processing parameters. The band-pass filtered signal provides accurate feedback about the actual RF power delivered to the plasma, enabling real-time optimization of processing conditions while maintaining productivity.
Solution Approach 2:
The patent replaces direct mechanical/electrical measurement of the distorted RF waveform with an electronic signal processing approach. Instead of attempting to measure the distorted voltage directly, the system uses electronic filtering and signal conditioning to extract the useful information, substituting a complex measurement problem with a more manageable electronic processing solution.
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 solution enables precise detection and control of the inductive RF voltage, maintaining a stable RF peak-to-peak voltage, thereby ensuring consistent plasma processing conditions.
Implementation Method 1
precisely detecting an inductive RF voltage induced to the substrate supporting member
Implementation Method 2
a matching device for matching impedance of the RF voltage to be supplied to the substrate supporting member from the RF generator, wherein the matching device comprises: a matching unit for matching the impedance of RF voltage; and an inductive RF detecting unit which an inductive RF detecting voltage by removing noise frequency elements except a waveform of the RF voltage from a waveform of an inductive RF voltage induced to the substrate supporting member
Data Source
AI summary
Disclosed is an apparatus and method for plasma processing, which facilitates to constantly control a RF voltage supplied to a substrate supporting member by precisely detecting an inductive RF voltage induced to the substrate supporting member for a plasma, the apparatus comprising: a substrate supporting member for supporting a substrate, installed in a reaction room of a processing chamber; a RF generator for supplying a RF voltage to the substrate supporting member so as to form plasma in the reaction room; and a matching device for matching impedance of the RF voltage to be supplied to the substrate supporting member from the RF generator, wherein the matching device comprises: a matching unit for matching the impedance of RF voltage; and an inductive RF detecting unit which an inductive RF detecting voltage by removing noise frequency elements except a waveform of the RF voltage from a waveform of an inductive RF voltage induced to the substrate supporting member, and supplies the detected inductive RF detecting voltage to the RF generator so as to control the RF voltage.