Two-Layer Plasma-Resistant Coating to Minimize Etching Sites
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Solution Overview
Problem
Existing plasma-resistant coating technologies for semiconductor process components suffer from etching issues due to cracks and pores in the coating layers, which act as starting points for plasma etching.
Innovation Solution
A two-layer coating film structure is developed, comprising a first ceramic coating layer formed by a spray coating method that fills pits on the substrate surface and includes fine pits, and a second plasma-resistant ceramic film formed using CVD, PVD, or ALD methods to cover the fine pits and minimize etching starting points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer plasma protective coating is formed on the substrate surface, then the substrate gains plasma resistance, but cracks and pores in the coating create starting points for plasma etching that spread to the entire surface
Solution Approach 1:
The coating system is divided into multiple layers (first coating layer, second coating layer, and optionally third coating layer) with different functions. The first layer provides crack resistance and fills substrate pits, the second layer provides plasma resistance with a dense structure, and the third layer (if present) provides additional plasma resistance. This segmentation allows each layer to address specific issues without compromising the others.
Solution Approach 2:
The patent uses composite coating structures combining different materials and deposition methods. The first coating layer uses spray coating methods with ceramic particles, the second layer uses CVD/PVD/ALD methods with different ceramic materials. This composite approach creates a coating system where each material contributes its strengths while compensating for the weaknesses of others.
2Manufacturing precision
If thermal spray method is used to form plasma protective coating, then coating can be applied to fill pits on substrate surface, but the coating always contains cracks and pores that serve as etching starting points
Solution Approach 1:
The coating process is segmented into multiple stages with different methods. The first coating layer uses spray coating to fill substrate pits and provide crack resistance. The second coating layer uses CVD/PVD/ALD methods to form a dense, crack-free plasma-resistant layer. This segmentation allows each method to perform its optimal function without the drawbacks of the other.
Solution Approach 2:
The first coating layer is applied in advance to fill the pits on the substrate surface and create a crack-resistant base layer. This preliminary action prepares the surface for the second coating layer, ensuring that the final coating system has both good surface coverage and high integrity without cracks or pores.
3Reliability
If aerosol deposition method is used to form coating layer, then coating with no cracks and almost no pores can be formed, but additional surface treatment (sand blasting, grinding) is required to increase roughness for adhesion
Solution Approach 1:
The coating system is segmented into multiple layers where the first coating layer (applied by spray coating) serves as an adhesion promoter with its inherent surface characteristics. The second coating layer (applied by CVD/PVD/ALD) provides the dense, crack-free plasma-resistant barrier. This segmentation eliminates the need for additional surface treatment steps while achieving both adhesion and density requirements.
Solution Approach 2:
The first coating layer acts as an intermediary between the substrate and the second coating layer. It provides a surface that is both adherent to the substrate and suitable for the deposition of the second layer, eliminating the need for sand blasting or grinding treatments that would otherwise be required to enhance adhesion.
4Reliability
If multiple coating layers are formed to improve plasma resistance, then etching resistance is enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The coating process is divided into distinct segments (first coating layer formation, second coating layer formation, and optionally third coating layer formation) where each segment addresses specific requirements. This segmentation allows for optimized process parameters at each stage while maintaining overall process efficiency and reducing complexity compared to attempting to achieve all functions in a single layer.
Solution Approach 2:
Each coating layer is designed to perform multiple functions: the first layer provides pit filling, crack resistance, and adhesion; the second layer provides plasma resistance and surface smoothness; the third layer (if present) provides additional plasma resistance. This multi-functionality reduces the need for additional specialized treatment steps, thereby reducing overall process complexity.
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 two-layer coating film structure significantly reduces plasma etching by minimizing the points where etching can concentrate, thereby enhancing plasma resistance and improving the stability and yield of semiconductor manufacturing processes.
Implementation Method 1
a first coating layer which is a ceramic coating layer formed without cracks on the surface of the substrate by a spray coating method other than thermal spray
Implementation Method 2
a second coating layer which is a plasma resistant ceramic film coated by one method of chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD)
Implementation Method 3
a second coating layer which is a plasma resistant ceramic film coated by one method of chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD)
Implementation Method 4
a second coating layer which is a plasma resistant ceramic film coated by one method of chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD)
Implementation Method 5
The two-layer coating film structure significantly reduces plasma etching by minimizing the points where etching can concentrate, thereby enhancing plasma resistance
Data Source
AI summary
Provided is a plasma-resistant two-layer coating film structure including: a ceramic or metal substrate having pits on a surface thereof; a first coating layer which is a ceramic coating layer formed without cracks on the surface of the substrate by a spray coating method other than thermal spray, the layer being coated to fill the pits on the surface of the substrate, fine pits accompanying ceramic particle bonding being formed on the surface, and the layer including ceramic polycrystalline bodies having a crystallite size of less than 300 nm; and a second coating layer which is a plasma resistant ceramic film, the layer being formed to have a surface roughness (Ra) of 0.2 μm or less without a separate grinding process and coated to cover the fine pits to form a surface in which positions that may serve as starting points of plasma etching are minimized.