Plasma RF Matching Circuit Using Negative Impedance Cancellation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing plasma processing apparatuses struggle to match high-frequency power supply-side impedance with plasma-side impedance across a wide frequency band, leading to inefficient power transfer and increased system complexity when dealing with multiple frequency components.

Innovation Solution

Incorporating a negative impedance portion in the high-frequency power supply circuit, which includes a negative impedance conversion circuit or metamaterial, to cancel plasma impedance and match impedances across a wide frequency range, accompanied by a boosting or amplifying part to achieve necessary voltage for plasma ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional impedance matching devices with two variable passive devices are used, then impedance matching can be achieved at a specific frequency, but the frequency band is limited and system complexity increases for wideband applications

Engineering Contradiction:

Improvefrequency band coverageVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transforms the passive impedance matching approach into an active impedance cancellation approach by changing the fundamental parameter of the matching mechanism. Instead of using variable passive components (capacitors and inductors) to adjust impedance, the invention uses an active circuit that generates a negative impedance signal to cancel the plasma impedance dynamically, enabling wideband operation without increasing system complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/passive impedance matching system with an electronic/active impedance cancellation system. The active circuit uses electronic signal processing to generate the negative impedance, substituting the mechanical adjustment of passive components with an electronic control mechanism that operates across a wide frequency range

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If multiple frequency components are processed, then plasma processing flexibility improves, but impedance matching becomes difficult and power transfer efficiency decreases

Engineering Contradiction:

Improvemulti-frequency processing capabilityVSAvoidpower transfer efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent implements a feedback mechanism where the active circuit monitors the plasma impedance and dynamically adjusts the negative impedance signal to maintain optimal cancellation across multiple frequency components. This feedback control ensures that power transfer efficiency is maintained even when processing signals with multiple frequency components, resolving the contradiction between processing flexibility and energy efficiency

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If conventional matching devices are used for wide frequency band, then frequency adaptability improves, but the number of components and system complexity increase

Engineering Contradiction:

Improvewide frequency band matchingVSAvoidnumber of components

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent creates a universal impedance matching solution where a single active circuit configuration can operate across a wide frequency band. The active impedance cancellation circuit serves multiple functions simultaneously - it provides impedance matching, enables wideband operation, and maintains power efficiency without requiring multiple separate matching devices or components for different frequency ranges

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 efficient impedance matching across a wide frequency band, allowing for effective power transfer and plasma ignition even with multiple frequency components, reducing system scaling and cost.

Implementation Method 1

a negative impedance portion (42) connected to the power supply path (41) and generating a negative impedance corresponding to a plasma impedance

Methodology Applied

Scientific EffectNegative impedance conversion:

Implementation Method 2

an electrode (10) to which a high-frequency power for generating plasma in the processing container (1) is applied

Methodology Applied

Scientific EffectPlasma generation through high-frequency power: Plasma

Data Source

PatentUS12476084B2Plasma processing apparatus, high-frequency power supply circuit, and impedance matching method

Publication Date: 2025.11.18 TOKYO ELECTRON LTD

AI summary

There is provided a plasma processing apparatus for performing plasma processing on a substrate, comprising: a processing container accommodating the substrate; an electrode to which a high-frequency power for generating plasma in the processing container is applied; a high-frequency power supply configured to apply the high-frequency power to the electrode; and a high-frequency power supply circuit configured to supply the high-frequency power from the high-frequency power supply to the electrode. The high-frequency power supply circuit comprises: a power supply path configured to supply a power from the high-frequency power supply to the electrode; and a matching device configured to match a high-frequency power supply-side impedance with a plasma-side impedance, the matching device comprising a negative impedance portion that is connected to the power supply path and realizes a negative impedance corresponding to a plasma-side impedance.