Ceramic-Coated Electrostatic Chuck Surface for Plasma Corrosion Control
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Solution Overview
Problem
Existing electrostatic chucks in the semiconductor industry face issues with plasma corrosion and particle contamination due to sharp edges and high surface roughness, which lead to corrosion of processing chambers and contamination of wafers during plasma etch and clean processes.
Innovation Solution
A substrate support assembly with a thermally conductive base and a ceramic body, featuring a protective ceramic coating and deposited elliptical mesas with rounded edges, which are resistant to plasma corrosion and reduce surface roughness, minimizing particle contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If bead blasting process is used to create surface features on ESC, then surface features are formed, but sharp edges and cracking occur causing particle contamination
Solution Approach 1:
The patent applies spheroidality by rounding the edges of mesas and valleys on the ESC surface. Instead of sharp edges created by traditional bead blasting, the invention creates curved surfaces with rounded corners and edges. This curvature eliminates stress concentration points that cause cracking and prevents particle generation during thermal expansion, directly solving the particle contamination problem while maintaining functional surface features.
Solution Approach 2:
The patent changes the surface roughness parameter by smoothing the valleys between mesas and rounding all edges. The invention transforms the rough, sharp-edged surface topology into a smooth, curved surface with controlled roughness parameters. This parameter change reduces particle trapping in valleys and eliminates particle generation from broken peaks, resolving the contradiction between forming surface features and preventing contamination.
2Ease of manufacture
If traditional ESC surface is used, then manufacturing is simpler, but plasma corrosion damages the processing chamber
Solution Approach 1:
The patent applies composite materials by creating a multi-layer surface structure on the ESC. The surface comprises mesas and valleys with specific geometric features, and this structured surface is coated with plasma-resistant materials such as ceramic coatings. This composite approach combines the functional benefits of surface features with the protective properties of resistant materials, solving the plasma corrosion problem while maintaining ease of manufacture through established coating processes.
3Temperature
If sharp-edged surface features are present on ESC, then thermal expansion occurs, but peaks break causing particle contamination on wafer backside
Solution Approach 1:
The patent directly addresses thermal expansion issues by implementing spheroidality through rounded edges and curved surfaces on all surface features. The rounded corners and edges of mesas eliminate stress concentration points that would otherwise cause peak breaking during thermal cycling. This curvature design allows the ESC to expand and contract thermally without generating particles, resolving the contradiction between thermal expansion functionality and particle contamination prevention.
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 enhanced plasma corrosion resistance and reduced particle contamination by using a protective ceramic coating and rounded mesas, ensuring the integrity of the electrostatic chuck and the cleanliness of wafers during processing.
Implementation Method 1
A substrate support assembly such as an electrostatic chuck that has a plasma resistant protective layer
Implementation Method 2
depositing a ceramic material through the plurality of elliptical holes of the mask to form a plurality of elliptical mesas
Implementation Method 3
depositing a ceramic material through the plurality of elliptical holes of the mask to form a plurality of elliptical mesas
Implementation Method 4
polishing a surface of a ceramic body of the electrostatic chuck to produce a polished surface
Implementation Method 5
an electrostatic chuck (ESC) (e.g., an edge of ESC during wafer processing)
Data Source
AI summary
A coated chamber component comprises a body and a protective ceramic coating deposited over a surface of the body, the protective ceramic coating being amorphous and comprising about 8-20% by weight yttrium, about 20-32% by weight aluminum, and about 60-70% by weight oxygen.