Slip Ring RF Isolation Layout to Prevent PECVD Arcing

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Solution Overview

Problem

In plasma enhanced chemical vapor deposition (PECVD) reactors, the challenge is to prevent electrical breakdown and arcing between radio frequency (RF) and non-RF power lines due to voltage differences, especially in limited spaces where maintaining sufficient clearance or creepage distance is not feasible.

Innovation Solution

The implementation of a slip ring system that transfers both RF and non-RF power through multiple adjacent channels, using capacitors to block AC or DC power and distribute RF power evenly among channels, minimizing voltage differences and reducing the risk of arcing, while allowing for closer proximity of power lines within the limited space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If clearance or creepage distance is increased between signal lines to prevent electrical breakdown, then reliability is improved, but the device complexity and space requirements worsen

Engineering Contradiction:

Improveprevention of electrical breakdownVSAvoidspace within reactor

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

A slip ring assembly is introduced as an intermediary component between the RF power supply and the electrode. This slip ring includes multiple adjacent channels that physically separate RF and non-RF signal lines, allowing them to transmit power without direct contact while maintaining electrical isolation. The slip ring acts as a mediator that enables close proximity of power lines without electrical breakdown by providing a structured intermediate barrier.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The slip ring assembly is segmented into multiple adjacent channels, each dedicated to specific signal line types (RF or non-RF). This segmentation creates distinct transmission paths with controlled spacing, allowing RF and non-RF lines to be closely positioned while maintaining sufficient clearance through the channel structure. The segmentation enables systematic organization of power lines to prevent arcing.

Inventive Principle:

Principle #1Segmentation

2Area of stationary object

If multiple adjacent channels are used to transfer both RF and non-RF power, then space utilization is improved, but voltage differences between channels may cause arcing

Engineering Contradiction:

Improvespace utilizationVSAvoidelectrical arcing

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The slip ring assembly is designed to maintain equipotential conditions between adjacent channels by controlling the electrical characteristics of each channel. The structure ensures that voltage differences between adjacent RF and non-RF channels remain below the breakdown threshold of the insulating material. This equipotential design prevents arcing while allowing close spacing of channels for efficient space utilization.

Inventive Principle:

Principle #12Equipotentiality

Solution Approach 2:

The electrical parameters of the slip ring channels are optimized to prevent arcing. The insulating material properties, channel spacing, and electrical potential distribution are carefully controlled to ensure that voltage differences between adjacent channels remain within safe limits. By adjusting these parameters, the system achieves close channel spacing without electrical breakdown.

Inventive Principle:

Principle #35Parameter changes

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 effectively prevents electrical arcing and damage by ensuring minimal voltage differences between adjacent channels, allowing the system to operate safely within the constrained space of a PECVD reactor, thereby protecting both the electrode and RF power supply.

Implementation Method 1

using capacitors to block AC or DC power and distribute RF power evenly among channels

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11784027B2Apparatuses and methods for avoiding electrical breakdown from RF terminal to adjacent non-RF terminal

Publication Date: 2023.10.10 LAM RES CORP

AI summary

An isolation system includes an input junction coupled to one or more RF power supplies via a match network for receiving radio frequency (RF) power. The isolation system further includes a plurality of channel paths connected to the input junction for distributing the RF power among the channel paths. The isolation system includes an output junction connected between each of the channel paths and to an electrode of a plasma chamber for receiving portions of the distributed RF power to output combined power and providing the combined RF power to the electrode. Each of the channel paths includes bottom and top capacitors for blocking a signal of the different type than that of the RF power. The isolation system avoids a risk of electrical arcing created by a voltage difference between an RF terminal and a non-RF terminal when the terminals are placed proximate to each other.