Rare Earth Oxide Thermal Spray Coating for Plasma Erosion Resistance

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Solution Overview

Problem

Conventional thermal spray coatings do not provide sufficient plasma erosion resistance under high plasma output conditions, leading to decreased device yield and quality defects in semiconductor and liquid crystal device fabrication.

Innovation Solution

A thermal spray powder composed of rare earth oxide particles with a crushing strength of 80 MPa or greater and a bulk specific gravity to true specific gravity ratio of 0.15 or greater, preferably produced as granulated and sintered particles, is used to form a coating with enhanced plasma erosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thermal spray coating is used, then the coating can be applied to members, but the plasma erosion resistance is insufficient under high plasma output conditions

Engineering Contradiction:
Improveplasma erosion resistanceVSAvoidetching process speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the material parameters of the thermal spray coating by using rare earth oxide particles with specific properties (crushing strength ≥80 MPa, bulk specific gravity to true specific gravity ratio ≥0.15) to achieve both high plasma erosion resistance and compatibility with high plasma output etching conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structure by combining rare earth oxide particles with specific physical properties to create a thermal spray coating that simultaneously provides protection against plasma erosion and maintains performance under high power density conditions

Inventive Principle:
Principle #40Composite materials

2Productivity

If high plasma output is used to shorten etching time, then productivity increases, but the thermal spray coating deteriorates due to insufficient plasma erosion resistance

Engineering Contradiction:
Improveetching process speedVSAvoidcoating durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies the coating material parameters (using rare earth oxides with atomic numbers 39 or 59-70, specific crushing strength and specific gravity ratio) to enable the coating to withstand high plasma output conditions while maintaining high etching process speed

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional thermal spray powder is used, then the coating formation is simple, but the particle disintegration and porosity increase under high plasma etching conditions

Engineering Contradiction:
Improvecoating formation simplicityVSAvoidcoating density
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the particle parameters (crushing strength ≥80 MPa, bulk specific gravity to true specific gravity ratio ≥0.15) to prevent particle disintegration and reduce porosity while maintaining simple coating formation processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary preparation of rare earth oxide particles with optimized physical properties before coating formation to ensure that the particles resist disintegration and minimize porosity during subsequent plasma etching processes

Inventive Principle:
Principle #10Preliminary action

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 thermal spray coating exhibits improved plasma erosion resistance, reducing the occurrence of defects and increasing device yield by suppressing particle disintegration and porosity, even under high plasma etching conditions.

Implementation Method 1

a thermal spray coating by plasma thermal spraying the above thermal spray powder

Methodology Applied
Scientific EffectPlasma heating: Plasma

Implementation Method 2

The particles in the thermal spray powder are composed of an oxide of any of the rare earth elements

Methodology Applied
Scientific EffectThermal melting: Melting

Implementation Method 3

the thermal spray coating exhibits improved plasma erosion resistance, reducing the occurrence of defects

Methodology Applied
Scientific EffectPlasma erosion resistance: Erosion

Implementation Method 4

particles composed of an oxide of any of the rare earth elements having an atomic number of 39 or from 59 to 70

Methodology Applied
Scientific EffectRare earth oxide protection: Refractory Material

Data Source

PatentUS7837967B2Thermal spray powder and method for forming thermal spray coating
Publication Date: 2010.11.23 FUJIMI INCORPORATED

AI summary

A thermal spray powder contains particles composed of an oxide of any of the rare earth elements having an atomic number of 39 or from 59 to 70. The crushing strength of the particles is 80 MPa or greater. The ratio of bulk specific gravity to true specific gravity of the thermal spray powder is 0.15 or greater. The particles are preferably granulated and sintered particles. The average particle size of primary particles constituting the granulated and sintered particles is preferably 6 μm or less.