RF Heater Cable Isolation for Substrate Support Impedance Control

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Solution Overview

Problem

Substrate processing systems face challenges with impedance shifts caused by heating elements in the electrode and edge ring, leading to reduced etch rates, wafer non-uniformity, and interference with RF plasma generation.

Innovation Solution

A cable and filter system with an isolation device, such as an inductor, is used to compensate for resonance frequencies generated by the heating elements. The isolation device is configured to either cancel or shift the resonance frequency relative to the operating frequencies of the RF power, thereby maintaining efficient RF power delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heating elements are used in the edge ring and electrode, then substrate temperature control is improved, but impedance shifts occur that interfere with RF plasma generation

Engineering Contradiction:

Improvesubstrate temperature controlVSAvoidimpedance shifts interfering with RF plasma generation

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

An isolation device is introduced as an intermediary component between the heating elements and the RF plasma generation system. This isolation device compensates for impedance shifts by introducing a counteracting impedance, thereby preventing the heating elements from interfering with RF plasma generation while maintaining their temperature control function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The isolation device changes the electrical parameter (impedance) of the cable system by introducing a compensating impedance that counteracts the impedance shifts caused by heating elements. This parameter change allows the system to maintain stable RF plasma generation despite the presence of heating elements

Inventive Principle:

Principle #35Parameter changes

2Temperature

If heating elements are powered during etching, then substrate temperature is maintained, but power interference reduces etch rates

Engineering Contradiction:

Improvesubstrate temperature maintenanceVSAvoidetch rate

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The isolation device acts as a mediator that separates the power delivery paths for heating elements and RF plasma generation. By compensating for impedance shifts, it prevents power interference that would otherwise reduce etch rates, allowing both heating and etching to proceed at optimal levels

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If heating elements are used, then wafer temperature uniformity can be controlled, but resonance frequencies are generated that disrupt RF operation

Engineering Contradiction:

Improvewafer temperature uniformityVSAvoidresonance frequencies disrupting RF operation

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The isolation device converts the harmful resonance frequencies generated by heating elements into a beneficial compensating impedance. By deliberately introducing this compensating impedance, the system transforms the disruptive resonance into a useful mechanism for maintaining stable RF operation while preserving wafer temperature uniformity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively compensates for impedance shifts caused by heating elements, reducing power interference with RF plasma generation, maintaining etch rates, and ensuring wafer uniformity.

Implementation Method 1

The isolation device is configured to compensate for a resonance frequency generated during operation of the edge ring and the at least one heating element

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

The isolation device has an impedance that is selected in accordance with the resonance frequency

Methodology Applied

Scientific EffectImpedance: Electrical Impedance Tomography

Implementation Method 3

The isolation device includes an inductor

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 4

The isolation device includes at least one of a ferrite bead and ferrite bead material

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentUS20250183015A1High power cable for heated components in RF environment

Publication Date: 2025.06.05 LAM RES CORP

AI summary

A cable and filter system for a substrate support includes a connector configured to connect to a power source, first plurality of wires configured to provide power from the power source to a heater element arranged within an edge ring of the substrate support, a second plurality of wires is configured to provide power from the power source to at least one heating element arranged within a ceramic layer of the substrate support, a filter module, and an isolation device. The first and second pluralities of wires are twisted together within the filter module. The isolation device is connected only to the first plurality of wires between the filter module and the heater element within the edge ring, and is configured to compensate for a resonance frequency generated during operation of the heater element within the edge ring and the at least one heating element within the ceramic layer.