Sintered Rare-Earth Ceramic Coating for Low-Shedding Reactor Components
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current corrosion-resistant coatings for semiconductor processing equipment, such as those using rare earth compounds, face issues like high cost, mechanical weakness, and particle shedding due to internal stresses and porosity, which are not effectively addressed by existing methods like PVD, CVD, and thermal plasma spray.
Innovation Solution
A corrosion-resistant component comprising a ceramic insulating substrate with a non-porous outer layer made of rare earth compounds and ytterbium oxide, which is sintered to achieve a thickness of at least 50 µm, porosity of at most 1%, and adhesion strength of at least 20 MPa, with an interposing layer to enhance stability and prevent particle shedding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermal plasma spray is used to apply rare earth compound coatings, then the coating process is widely applicable and can be performed, but the resulting coatings have porosity greater than 1% and high density of microcracks, making them prone to particle shedding
Solution Approach 1:
The patent changes the fundamental manufacturing parameter from thermal plasma spray to solid-state sintering. By sintering the rare earth compound powder directly onto the substrate at high temperature (typically 1600-2000°C) in a controlled atmosphere, the process eliminates the porosity and microcrack formation inherent in plasma spray methods, achieving dense, crack-free coatings with minimal particle shedding while maintaining manufacturing feasibility
Solution Approach 2:
The patent replaces the thermal plasma spray mechanical system with a solid-state sintering process. Instead of using plasma to deposit and bond coating material, the invention uses direct thermal diffusion and bonding through sintering, where the rare earth compound powder is heated to烧结 temperature to form a dense, adherent coating layer that is inherently free of the defects associated with plasma spray
2Length of stationary object
If thick PVD coatings are applied to achieve thickness greater than 10 μm, then the coating thickness requirement is met, but internal stresses cause the coatings to spall
Solution Approach 1:
The patent introduces an intermediary bonding layer or transition zone during the sintering process. This intermediary layer, formed by the gradual densification and bonding of rare earth compound powder particles, acts as a stress buffer that accommodates thermal expansion differences between the coating and substrate, enabling thick coatings to be applied without spalling while maintaining strong adhesion
Solution Approach 2:
The patent changes the deposition mechanism from physical vapor deposition to solid-state sintering. This parameter change fundamentally alters how the coating bonds to the substrate, allowing thick coatings to be formed through progressive densification and interdiffusion rather than layer-by-layer deposition, thereby eliminating the internal stress accumulation that causes spalling in thick PVD coatings
3Reliability
If rare earth compound coatings are applied to provide corrosion resistance, then corrosion protection is achieved, but the coatings are mechanically weak and expensive
Solution Approach 1:
The patent creates a composite structure by forming an intimate bond between the rare earth compound coating and the substrate through sintering. The resulting composite material combines the corrosion resistance of the rare earth compound with the mechanical strength of the substrate, achieving both protective and structural properties in a single integrated component rather than as a separate coating layer
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 solution provides a physically and chemically stable, corrosion-resistant layer that prevents particle shedding and maintains integrity in harsh semiconductor processing environments, addressing the limitations of existing coatings by ensuring high adhesion strength and reduced porosity.
Implementation Method 1
a corrosion-resistant non-porous outer layer adhered to the ceramic insulating substrate, the corrosion-resistant non-porous outer layer having a thickness of at least 50 μm, a porosity of at most 1%
Implementation Method 2
a sintering aid added to the rare-earth compound in the range from about 300 ppm to about 20% by weight based upon total weight of the rare-earth compound
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A corrosion-resistant component configured for use with a semiconductor processing reactor, the corrosion-resistant component comprising: a) a ceramic insulating substrate; and, b) a white corrosion-resistant non-porous outer layer associated with the ceramic insulating substrate, the white corrosion-resistant non-porous outer layer having a thickness of at least 50 µm, a porosity of at most 1%, and a composition comprising at least 15% by weight of a rare earth compound based on total weight of the corrosion-resistant non-porous layer; and, c) an L* value of at least 90 as measured on a planar surface of the white corrosion-resistant non-porous outer layer. Methods of making are also disclosed.