Tungsten-Silicon-Boron Thermal Spray Coating for Plasma Etching
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Solution Overview
Problem
Current ceramic coatings used in plasma etching chambers for semiconductor production are not effective in suppressing dust generation and wear caused by halogen gas plasma, particularly due to the degradation of rare earth oxyfluoride coatings and the instability of silicon-based materials.
Innovation Solution
A thermal spray coating composed of tungsten as the matrix phase with dispersed oxides of silicon and boron, which forms a glassy phase that prevents cracking and enhances mechanical properties, allowing for effective suppression of dust and wear during plasma exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic coatings containing oxyfluorides of rare earth metals are used, then plasma resistance is improved, but dust generation increases due to depletion by plasma exposure
Solution Approach 1:
The patent uses a composite coating system consisting of an undercoat layer (aluminum oxide or aluminum nitride) and a topcoat layer (silicon oxide or silicon nitride). This composite structure combines the plasma resistance of the undercoat with the low-dust generation properties of the topcoat, resolving the contradiction between plasma resistance and dust generation.
2Object-generated harmful factors
If silicon material is used as surface modification material, then dust generation is reduced, but wear resistance decreases requiring frequent recoating
Solution Approach 1:
The patent creates a composite coating where silicon oxide or silicon nitride topcoat is applied over an aluminum oxide or aluminum nitride undercoat. The undercoat provides durable wear resistance while the topcoat minimizes dust generation, achieving both low dust generation and long coating life.
Solution Approach 2:
The coating system assigns different functional properties to different layers: the undercoat layer provides mechanical durability and plasma resistance, while the topcoat layer provides low dust generation. This local differentiation of material properties resolves the contradiction between durability and dust suppression.
3Ease of manufacture
If metallic materials such as aluminum alloys are used for chamber construction, then ease of manufacture is improved, but resistance to halogen gas plasma deteriorates
Solution Approach 1:
The patent applies ceramic coating layers (aluminum oxide, aluminum nitride, silicon oxide, or silicon nitride) over metallic chamber components. This composite approach maintains the ease of manufacturing metallic chambers while providing the plasma resistance of ceramic materials through the coating layers.
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 tungsten-silicon-boron thermal spray coating significantly reduces dust generation and wear, maintaining structural integrity and plasma resistance, even under fluorine-containing gas exposure, thereby improving semiconductor chip production yields.
Implementation Method 1
Plasma etching removes the material not only through the physical sputtering effect, but also through the chemical sputtering effect
Implementation Method 2
Plasma etching removes the material not only through the physical sputtering effect, but also through the chemical sputtering effect by exposing the wafer to plasma using a halogenated gas
Implementation Method 3
a thermal spray coating containing tungsten as the matrix phase and oxides containing silicon and boron as the dispersed phase
Data Source
AI summary
To provide a new tungsten-based thermal spray coating suitable as e.g. a component for plasma etching device using halogen gas, and a material for thermal spraying for obtaining the thermal spray coating.A thermal spray coating characterized by containing tungsten as a matrix phase and oxides containing silicon and boron as a dispersed phase, and a component for plasma etching device having such a thermal spray coating. A material for thermal spraying characterized by containing from 1 to 7 wt % of silicon, from 0.5 to 3 wt % of boron and the reminder being tungsten and unavoidable impurities, and a method for producing a thermal spray coating by thermally spraying the material for thermal spraying.