PEPVD Coated Electrostatic Chuck Plasma Erosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coatings for electrostatic chucks in plasma processing chambers are susceptible to plasma erosion, contamination, and mechanical abrasion, with conventional plasma spray Y2O3 coatings having high surface roughness and porosity, and other deposition methods failing to produce thick, crack-resistant, and adherent ceramic coatings.
Innovation Solution
The development of advanced Yttria and Alumina coatings using plasma-enhanced physical vapor deposition (PEPVD) with a hybrid ceramic composition, such as Y2O3/Al2O3, which are applied in a vacuum environment with ionized plasma to achieve a dense, smooth, and hard surface with improved thermal conductivity and electrical resistivity, and optionally layered with a second coating for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If plasma spray Y2O3 coating is used, then plasma erosion resistance is improved, but surface roughness and porosity increase leading to particle generation
Solution Approach 1:
The patent changes the deposition parameters by using PEPVD instead of plasma spray, achieving dense coating with low porosity and smooth surface finish (Ra<1.0μm) while maintaining plasma erosion resistance. The coating is deposited at controlled temperature and pressure to prevent particle formation.
Solution Approach 2:
The patent uses composite ceramic coatings combining Y2O3 with other materials (such as Al2O3, ZrO2, or SiC) to achieve both plasma erosion resistance and low particle generation. The composite structure provides enhanced mechanical properties and reduced surface roughness compared to pure Y2O3.
2Length of stationary object
If plasma spray coating is used, then coating thickness can be increased, but coating cracks and delamination occur
Solution Approach 1:
The patent changes the deposition method to PEPVD which allows thick coating deposition without the high residual stresses that cause cracking in plasma spray. The controlled deposition parameters and lower deposition temperature prevent coating delamination while achieving thicknesses greater than 100μm.
Solution Approach 2:
The patent optimizes the coating structure at different depths, with a dense, fine-grained surface layer for erosion resistance and a graded transition zone to the substrate for stress relief. This local quality variation prevents cracking while maintaining thickness.
3Reliability
If conventional deposition methods are used, then coating adhesion can be improved, but deposition rate is too low for thick coating
Solution Approach 1:
The patent uses PEPVD parameters that optimize both adhesion and deposition rate simultaneously, achieving high coating quality with thickness >100μm in practical production time. The plasma-enhanced process provides sufficient ion energy for strong adhesion while maintaining high deposition flux.
4Strength
If plasma spray Al2O3 coating is used, then hardness is improved, but aluminum contamination of substrate occurs
Solution Approach 1:
The patent uses composite coatings where Al2O3 is combined with other ceramics (Y2O3, ZrO2, SiC) to reduce aluminum content and prevent contamination while maintaining hardness. The composite structure provides mechanical properties similar to pure Al2O3 without the contamination issue.
Solution Approach 2:
The patent creates a graded coating structure with different material compositions at different depths, placing contamination-resistant materials at the plasma-exposed surface while maintaining hardness throughout the coating thickness.
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 PEPVD-coated electrostatic chucks exhibit reduced plasma erosion, low porosity, and increased hardness, providing long service life with minimal particle contamination and improved plasma process quality, while allowing for thick, crack-resistant coatings without delamination.
Implementation Method 1
plasma-enhanced physical vapor deposition (PEPVD)
Implementation Method 2
applied in a vacuum environment with ionized plasma to achieve a dense, smooth, and hard surface
Data Source
AI summary
An advanced coating for electrostatic chuck used in plasma processing chamber is provided. The advanced coating is formed using plasma enhanced physical vapor deposition. The coating is generally of Y2O3/Al2O3, although other material combinations can be used. Also, a multi-layered coating can be formed, such that an intermediate coating layer can be formed using standard plasma spray, and a top coating can be formed using PEPVD. The entire ESC assembly can be “packaged” by the coating.