Twin Wire Arc Spray Composite Coating for Deposition Chamber
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Solution Overview
Problem
Existing methods for modifying chamber surfaces in deposition processes to enhance adherence of plasma byproducts are inadequate, leading to contamination and inefficiencies due to non-continuous coatings and potential delamination, which affects productivity and recyclability.
Innovation Solution
A composite Twin Wire Arc Spray (TWAS) coating process involving a bond coat and a top coat with specific surface roughness characteristics is applied to deposition chamber components, ensuring a continuous and high-bond-strength coating that prevents delamination and enhances byproduct adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If known surface roughing techniques (grit blasting, chemical etching) are applied to chamber surfaces, then surface roughness is increased to enhance byproduct adherence, but the degree of adherence is insufficient and coatings may delaminate
Solution Approach 1:
The invention applies a composite coating system consisting of a bond coat layer and a top coat layer. The bond coat (e.g., aluminum or aluminum alloy) provides strong adhesion to the substrate, while the top coat (e.g., aluminum or aluminum alloy with different composition) provides enhanced surface roughness for byproduct trapping. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both strong adherence and reliable continuous coverage.
Solution Approach 2:
The coating is divided into multiple functional layers (bond coat and top coat) with distinct purposes. The bond coat layer addresses adhesion requirements, while the top coat layer addresses surface roughness and byproduct trapping requirements. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between adherence strength and coating reliability.
2Quantity of substance
If coatings are applied to roughen chamber wall surfaces, then byproduct trapping capacity is improved, but the coatings may delaminate and contaminate work pieces
Solution Approach 1:
The composite coating system with bond coat and top coat provides both enhanced byproduct trapping capacity and delamination resistance. The bond coat ensures strong substrate attachment, while the top coat creates sufficient surface roughness for byproduct accumulation, preventing both delamination and contamination issues.
Solution Approach 2:
The invention controls coating parameters including thickness (e.g., bond coat 0.5-2 mils, top coat 0.5-2 mils), surface roughness (Ra 10-50 microns), and composition to optimize both byproduct trapping capacity and delamination resistance. By carefully adjusting these parameters, the coating provides adequate roughness for byproduct accumulation while maintaining continuous coverage and strong adhesion.
3Productivity
If chamber surfaces are modified to increase byproduct adherence, then processing time between cleanings is extended, but existing methods do not provide adequate surface roughness or adherence volume
Solution Approach 1:
The composite coating system achieves superior surface roughness (Ra 10-50 microns) and adherence volume by combining bond coat and top coat layers. This enhanced surface morphology significantly increases byproduct trapping capacity, extending processing time between cleanings and improving productivity.
Solution Approach 2:
The invention creates a three-dimensional rough surface morphology on the chamber walls through the composite coating structure. This dimensional transformation from smooth to rough surfaces dramatically increases the volume available for byproduct accumulation, enhancing adherence capacity and extending operational cycles.
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 composite TWAS coating provides a continuous, high-bond-strength surface that effectively traps deposition byproducts, reducing contamination and enabling longer processing times and improved recyclability of valuable species like tantalum.
Implementation Method 1
Twin Wire Arc Spraying (TWAS) processes are particularly useful thermal spraying processes
Implementation Method 2
A high current is applied across the wires causing an electrical arc to form across the tips of the wires. The electric current then melts the feed wire portion in the arc zone
Implementation Method 3
The gas stream sprays the molten metal onto the work surface forming a coating
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3B
AI summary
Methods and apparatuses are disclosed for applying a twin wire arc spray composite coating to achieve surface effects on a substrate having predetermined characteristics.