Plasma Generator Impedance Matching Against RF Source Interference

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Solution Overview

Problem

In plasma generation systems using multiple high-frequency power sources, frequency interference leads to unstable plasma generation due to noise interference.

Innovation Solution

Implementing a system with multiple plasma generators, each connected to a high-frequency power source and a matcher, along with a directional coupler, filter, and power monitor to control impedance matching and reduce noise, ensuring stable plasma generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple high-frequency power sources are used for plasma generation, then plasma generation capability is improved, but frequency interference causes noise and destabilizes plasma generation

Engineering Contradiction:

Improveplasma generation capabilityVSAvoidplasma generation stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

A directional coupler is introduced as an intermediary device between the high-frequency power source and plasma generator. This coupler extracts reflected wave components and directs them to a filter, mediating the interaction between power sources and preventing frequency interference from destabilizing the plasma generation process

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The reflected wave component, which contains the frequency interference and noise, is extracted from the main power transmission path using a directional coupler. By separating this harmful component, the system maintains stable plasma generation while still utilizing multiple high-frequency power sources for enhanced capability

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If reflected wave components are monitored and filtered, then plasma generation stability is improved, but device complexity increases due to additional components

Engineering Contradiction:

Improveplasma generation stabilityVSAvoidsystem component count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A feedback control mechanism is implemented where the power monitor continuously measures the reflected wave component, and this information is used to adjust the matcher settings. This feedback loop automatically maintains optimal impedance matching and plasma stability without requiring manual intervention, justifying the added component complexity

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis and self-adjustment through the feedback mechanism. The power monitor detects reflected wave variations, and the matcher automatically adjusts to maintain optimal conditions, enabling the system to self-correct stability issues without external control

Inventive Principle:

Principle #25Self-service

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 system achieves stable plasma generation by minimizing noise interference, enabling consistent and efficient processing of substrates.

Implementation Method 1

a directional coupler disposed at a subsequent stage of the high-frequency oscillator, and configured to extract a part of a traveling wave component from the high-frequency oscillator and a part of a reflected wave component from a corresponding matcher

Methodology Applied

Scientific EffectElectromagnetic wave extraction:

Implementation Method 2

a filter configured to remove a noise signal included in the reflected wave component extracted by the directional coupler

Methodology Applied

Scientific EffectNoise filtering: Filter (electronic)

Implementation Method 3

a high-frequency oscillator configured to oscillate a high-frequency

Methodology Applied

Scientific EffectElectromagnetic oscillation:

Implementation Method 4

a plurality of matchers installed between the plurality of high-frequency power sources and the plurality of plasma generators, and configured to respectively match load impedances of the plasma generators with output impedances of the high-frequency power sources

Methodology Applied

Scientific EffectImpedance matching: Electrical Resistance

Implementation Method 5

activating a process gas such as a precursor gas, a reaction gas, or the like, which is supplied into the process chamber, by using plasma

Methodology Applied

Scientific EffectPlasma generation: Plasma

Data Source

PatentUS12492476B2Substrate processing apparatus, method of processing substrate, method of manufacturing semiconductor device, and plasma generation device preliminary

Publication Date: 2025.12.09 KOKUSAI DENKI KK

AI summary

There is provided a technique that includes: high-frequency power sources supplying power to plasma generators; and matchers installed between the high-frequency power sources and the plasma generators and matching load impedances of the plasma generators with output impedances of the high-frequency power sources, wherein at least one of the high-frequency power sources includes: a high-frequency oscillator; a directional coupler at a subsequent stage of the high-frequency oscillator, which extracts a part of a traveling wave component from the high-frequency oscillator and a part of a reflected wave component from the matcher; a filter removing a noise signal in the reflected wave component extracted by the directional coupler; and a power monitor measuring the reflected wave component after passing through the filter and the traveling wave component extracted by the directional coupler and feedback-controlling the matcher to reduce a ratio between the reflected wave component and the traveling wave component.