RF Isolation Filters for Nanosecond Pulsed Plasma Chambers

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Solution Overview

Problem

Existing plasma processing systems face challenges in efficiently transferring RF power from generators to plasma chambers due to mismatched impedances, leading to inefficiencies and potential interference between RF and nanosecond pulser signals.

Innovation Solution

Incorporating a plasma system with an RF driver, a nanosecond pulser, a high pass filter between the RF driver and the plasma chamber, and a low pass filter between the nanosecond pulser and the plasma chamber, along with specific filter components like capacitors and inductors to isolate and filter signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If RF power is transmitted through RF cables and networks to the plasma chamber, then power transfer is enabled, but impedance mismatch between the fixed impedance of the RF generator and the variable impedance of the plasma chamber causes inefficiency

Engineering Contradiction:

ImproveRF power transfer efficiencyVSAvoidenergy loss due to impedance mismatch

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

An RF impedance matching network is introduced as an intermediary component between the RF generator and the plasma chamber. This matching network transforms the variable impedance of the plasma chamber to match the fixed impedance of the RF generator, enabling efficient power transfer and reducing energy loss due to impedance mismatch.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If RF driver and nanosecond pulser both drive signals into the plasma chamber, then plasma processing functionality is enhanced, but signal interference between RF and nanosecond pulser occurs

Engineering Contradiction:

Improveplasma processing functionalityVSAvoidsignal interference

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The plasma chamber is divided into distinct electrical zones by introducing separate filtering paths for RF and nanosecond pulser signals. High pass filters are placed in the RF signal path while low pass filters are placed in the nanosecond pulser path, segmenting the signal frequencies and preventing interference between the two signal types while maintaining both plasma processing functionalities.

Inventive Principle:

Principle #1Segmentation

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

Enhances the efficient transfer of RF power and isolates signals, reducing interference and improving the stability and performance of plasma processing.

Implementation Method 1

a high pass filter disposed between the RF driver and the plasma chamber

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Implementation Method 2

a low pass filter disposed between the nanosecond pulser and the plasma chamber

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Implementation Method 3

the capacitor has a capacitance less than about 500 pF

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 4

the inductor has an inductance less than about 10 nH

Methodology Applied

Scientific EffectInductance: Inductor

Data Source

PatentUS12456604B2Nanosecond pulser RF isolation for plasma systems

Publication Date: 2025.10.28 EAGLE HARBOR TECHNOLOGIES INC

AI summary

Embodiments of the invention include a plasma system. The plasma system includes a plasma chamber; an RF driver configured to drive bursts into the plasma chamber with an RF frequency; a nanosecond pulser configured to drive pulses into the plasma chamber with a pulse repetition frequency, the pulse repetition frequency being less than the RF frequency; a high pass filter disposed between the RF driver and the plasma chamber; and a low pass filter disposed between the nanosecond pulser and the plasma chamber.