Rare Earth Multilayer Sprayed Coating for Erosion and Particle Control
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Solution Overview
Problem
Existing electrostatic chucks in semiconductor manufacturing processes face high production costs and require high voltages for sufficient adsorption, and coatings in plasma etching apparatuses suffer from erosion and particle generation, which affect process yield.
Innovation Solution
A multilayer sprayed coating with a lower layer of rare earth oxide and a surface layer of rare earth fluoride or oxyfluoride, optimized for thickness, hardness, porosity, and roughness, is applied using thermal spraying methods to enhance erosion resistance and reduce particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If atmospheric plasma spraying is used to form erosion-resistant coating, then erosion resistance is improved, but particle generation occurs and process yield deteriorates
Solution Approach 1:
The patent changes the particle size parameter of the spraying material to below 10 μm (specifically 1-5 μm), which fundamentally alters the coating formation process. This parameter change enables the coating to be dense without generating particles during etching, resolving the contradiction between erosion resistance and particle generation
Solution Approach 2:
The patent uses composite spraying material containing both rare earth oxide (for erosion resistance) and rare earth fluoride (for low particle generation). This composite approach combines the advantages of both materials to achieve high erosion resistance while minimizing particle generation during plasma etching
2Ease of manufacture
If large average particle size (≥10 μm) is used for spraying, then flowability is improved, but coating density decreases and particle generation increases
Solution Approach 1:
The patent changes the particle size parameter to a specific range (1-5 μm, below 10 μm) that optimizes both flowability and coating density. This precise parameter control allows fine particles to maintain good flowability while forming dense coatings without particle generation
3Reliability
If high voltage (2000-3000 V) is applied to Coulomb force type electrostatic chuck, then adsorption power is improved, but production cost increases
Solution Approach 1:
The patent changes the volume resistivity parameter of the dielectric layer to 1×10^9 to 1×10^12 Ω·cm, which enables Johnson-Rahbek force mechanism to achieve sufficient adsorption power at lower voltages (below 2000 V), thereby reducing production costs while maintaining reliable adsorption
4Reliability
If sintered ceramic with high purity is used for Coulomb force type electrostatic chuck, then volume resistivity is improved, but production cost increases
Solution Approach 1:
The patent uses composite material containing rare earth oxide and rare earth fluoride, which achieves the required volume resistivity (1×10^9 to 1×10^12 Ω·cm) at lower cost compared to high-purity sintered ceramic. This composite approach maintains reliable electrical properties while reducing production cost
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 coating exhibits stable volume resistivity across temperature variations and superior erosion resistance, reducing particle generation and maintaining process yield in halogen series gas atmospheres.
Implementation Method 1
a sprayed coating obtained by thermal spraying with particles having a large average particle size
Implementation Method 2
a dielectric layer portion has a volume resistivity of over 1×10^15 Ω·cm
Implementation Method 3
an erosion-resistant coating is generally formed by atmospheric plasma spraying (APS) which supplies rare earth compound as a raw material
Implementation Method 4
initial generation of particles are suppressed in comparison with a yttrium oxide sprayed coating formed by APS
Data Source
AI summary
A sprayed coating having a multilayer structure including a lower layer made a sprayed coating containing a rare earth oxide, and a surface layer made of another sprayed coating containing a rare earth fluoride and/or a rare earth oxyfluoride, the multilayered sprayed coating having a volume resistivity at 23° C. and a volume resistivity at 200° C., the volume resistivity at 23° C. being 1×109 to 1×1012 Ω·cm, and a temperature index of the volume resistivities defined by the ratio of the volume resistivity at 200° C. to the volume resistivity at 23° C. being 0.1 to 10.