Dielectric Window Gap for Plasma Stability

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Solution Overview

Problem

Conventional plasma processing apparatuses face issues with plasma stability deterioration due to microwave propagation to the surrounding body, which also fails to adequately protect the inner surface of the processing chamber from contamination.

Innovation Solution

A plasma processing apparatus with a dielectric window and a surrounding body made of dielectric material, where the dielectric window and surrounding body are separated by a predetermined gap to absorb microwaves and prevent excessive discharge, while the dielectric window's recess with a protrusion protects the chamber's inner surface from plasma exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a surrounding body made of dielectric material is added to protect the inner surface of the processing chamber, then the protection of the inner surface is improved, but the stability of the plasma deteriorates due to microwave propagation to the surrounding body

Engineering Contradiction:

Improveprotection of inner surfaceVSAvoidstability of plasma

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

A gap is introduced as an intermediary space between the dielectric window and the surrounding body. This gap prevents direct microwave propagation to the surrounding body while maintaining the protective function, thereby resolving the contradiction between protection and plasma stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the dielectric window and surrounding body are placed close to each other to maximize protection, then the protection effect is improved, but microwave propagation causes excessive discharge and plasma instability

Engineering Contradiction:

Improveprotection effectVSAvoidexcessive discharge

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The harmful microwave propagation path is extracted or blocked by introducing a gap between the dielectric window and surrounding body. This removes the direct coupling that causes excessive discharge while preserving the protective function against plasma exposure.

Inventive Principle:

Principle #2Taking out (Extraction)

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 configuration enhances plasma stability by absorbing microwaves and suppressing excessive discharge, while effectively protecting the processing chamber's inner surface from contamination, maintaining optimal plasma conditions for substrate processing.

Implementation Method 1

the dielectric window and the surrounding body are separated from each other in a vertical direction with a predetermined gap therebetween

Methodology Applied

Scientific EffectMicrowave absorption: Absorption (EM radiation)

Implementation Method 2

a substrate mounted on the table is processed by a plasma generated below the dielectric window by supplying a microwave to the slot plate

Methodology Applied

Scientific EffectPlasma generation: Plasma

Data Source

PatentUS10312057B2Plasma processing apparatus

Publication Date: 2019.06.04 TOKYO ELECTRON LTD

AI summary

A plasma processing apparatus includes a processing chamber, a table disposed in the processing chamber, a dielectric window provided at the processing chamber, and a surrounding body made of a dielectric material surrounding a processing space between the table and the dielectric window. The dielectric window and the surrounding body are separated from each other in a vertical direction with a predetermined gap therebetween.