Shower Head Electrode Flow Paths to Prevent Plasma Discharge

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Solution Overview

Problem

Abnormal discharge occurs inside the shower head of a plasma processing apparatus due to insufficient pressure reduction in the gas flow paths, leading to potential damage and disruption of processing gas supply.

Innovation Solution

The shower head design includes elongated slit-shaped second gas flow paths in the backing member, with a longer radial length than circumferential length, and narrowed portions in the first gas flow paths to enhance conductance and reduce pressure at the boundary between the upper electrode and backing member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional gas flow paths are used in the shower head, then the structure is simple, but abnormal discharge occurs due to insufficient pressure reduction

Engineering Contradiction:

Improveprevention of abnormal dischargeVSAvoidgas flow path structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the gas flow paths by making the second gas flow paths elongated with specific length ratios (radial length longer than circumferential length) and adding narrowed portions to the first gas flow paths. These parameter changes increase the conductance and pressure reduction capability of the gas flow paths, preventing abnormal discharge while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The gas flow path is divided into multiple segments: first gas flow paths in the electrode and second gas flow paths in the backing member. Each segment has specific structural features (elongated shape, narrowed portions) that work together to achieve progressive pressure reduction. This segmentation allows the system to achieve reliable pressure control without requiring a completely complex redesign.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the gas flow paths have sufficient conductance to reduce pressure, then abnormal discharge is prevented, but the flow path design becomes more complex

Engineering Contradiction:

Improvestable gas supplyVSAvoidflow path fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent specifies particular geometric parameters for the flow paths including the elongated shape with radial length exceeding circumferential length, and narrowed portions at specific locations. These parameter changes optimize the conductance for pressure reduction while being manufacturable using standard plasma processing apparatus fabrication techniques.

Inventive Principle:

Principle #35Parameter changes

3Stress or pressure

If elongated slit-shaped second gas flow paths are used, then pressure reduction is enhanced, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvepressure reduction in gas flow pathsVSAvoidelongated hole dimensions

Core Design Contradiction:

Stress or pressureVSManufacturing precision

Solution Approach 1:

The patent defines specific dimensional relationships for the elongated slit-shaped holes, requiring the radial length to be longer than the circumferential length. This parameter specification optimizes the pressure reduction function while providing clear manufacturing guidelines that balance precision requirements with fabrication capability.

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 configuration effectively prevents abnormal discharge by ensuring sufficient pressure reduction in the gas flow paths, thereby protecting the shower head components and maintaining stable gas supply.

Implementation Method 1

a total pressure drop occurs along the first and second gas flow paths

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Implementation Method 2

enhance conductance and reduce pressure at the boundary between the upper electrode and backing member

Methodology Applied

Scientific EffectConductance:

Data Source

PatentUS12586763B2Shower head electrode assembly and plasma processing apparatus

Publication Date: 2026.03.24 TOKYO ELECTRON LTD

AI summary

There is provided a shower head electrode assembly of a plasma processing apparatus, comprising: an electrode having a plurality of first gas flow paths and having a surface exposed to plasma; and a backing member attached to the electrode and having a plurality of second gas flow paths which communicate with the plurality of first gas flow paths. Each of the plurality of second gas flow paths is a slit-shaped elongated hole, and is configured such that a length of the elongated hole in radial direction is longer than a length of the elongated hole in circumferential direction with respect to a central axis of the shower head electrode assembly.