Yttrium Aluminum Silicate Glass Ceramic Coating for Semiconductor Chambers
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Solution Overview
Problem
Current coatings for ceramics in semiconductor manufacturing, such as YAG and yttria, are insufficient in producing smooth and dense plasma-resistant layers, as they tend to replicate substrate defects and are not effective against halide-based plasmas like fluorine or chlorine, leading to porosity and roughness.
Innovation Solution
A rare earth coating composition comprising 20-90 mol % SiO2, 0-60 mol % Al2O3, and 10-80 mol % rare earth oxides or fluorides, with a glassy or glass-ceramic structure, that includes at least 5 mol % rare earth fluorides to enhance plasma resistance and thermal expansion matching, applied as a glaze to create a smooth and dense surface on ceramic substrates like alumina and AlN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plasma sprayed coating is used, then coating can be applied to ceramic substrates, but the coating becomes porous and rough
Solution Approach 1:
The patent changes the chemical composition parameters of the coating material by incorporating specific ratios of SiO2 (20-90 mol%), Al2O3 (0-60 mol%), and rare earth oxides/fluorides (10-80 mol%). This compositional parameter change enables the coating to achieve both applicability to rough substrates and smooth final surface, resolving the contradiction between ease of manufacture and manufacturing precision.
2Manufacturing precision
If thin film deposition methods are used, then dense and smooth coatings can be generated, but substrate defects are transferred to the coating surface
Solution Approach 1:
The patent uses a glassy matrix as an intermediary medium that fills and smooths over substrate defects such as grain pull-out and scratches. The glassy phase acts as a mediator between the defective ceramic substrate and the final coating surface, preventing defect transfer while maintaining coating density and smoothness.
Solution Approach 2:
The coating is designed as a composite material system combining SiO2, Al2O3, and rare earth oxides/fluorides in specific proportions. This composite structure creates a glassy matrix that can accommodate and mask substrate imperfections, resolving the contradiction between achieving smooth surfaces and maintaining defect-free coatings.
3Object-affected harmful factors
If YAG or yttria coatings are used, then plasma resistance is improved, but surface roughness and porosity increase
Solution Approach 1:
The patent creates a composite coating system where rare earth oxides/fluorides provide plasma resistance while SiO2 forms a glassy matrix that ensures surface smoothness and density. This composite approach resolves the contradiction between achieving plasma erosion resistance and maintaining low surface roughness.
Solution Approach 2:
The coating provides different local properties: rare earth oxides/fluorides concentrated in specific phases provide plasma resistance, while the SiO2-rich glassy matrix provides surface smoothness and density. This local differentiation of material properties resolves the contradiction between plasma resistance and surface quality.
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 rare earth coating provides improved plasma erosion resistance, reduces surface roughness to less than 1.5 μm, and minimizes porosity, resulting in a smooth, defect-free surface that resists halide-based plasma exposure, enhancing semiconductor processing by reducing particle contamination and facilitating easier maintenance.
Implementation Method 1
Dense and smooth coatings with high plasma erosion resistance are ideal for reduced particle defect on semiconductor processing
Implementation Method 2
The coating is preferably a glassy coating or a glass ceramic coating
Implementation Method 3
the fluorides increase the glass formation range of the REX glass, as well as also increasing the coefficient of thermal expansion (CTE) of the glass to have a better match with the substrate
Implementation Method 4
The open porosity of the coating is preferably less than 5.0%, more preferably less than 3.0% or less than 2.8%
Data Source
AI summary
Articles may be protected against halide plasma, by applying a rare earth-containing glaze to the surface of the article. The glaze may be a coating comprising; 20 to 90 mol % SiO2, 0 to 60 mol % Al2O3, 10 to 80 mol % rare earth oxides and/or rare earth fluorides (REX), wherein SiO2+Al2O3+REX≥60 mol %.