Electrostatic Chuck with Integral Sintered Electrode
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Solution Overview
Problem
Conventional electrostatic chucks suffer from reduced adhesion force, increased gas leakage, and decreased heat transfer due to surface roughness and erosion during plasma processing, leading to frequent replacements and yield reduction.
Innovation Solution
A polycrystalline ceramic electrostatic chuck with an electrode layer integrally sintered into a ceramic dielectric substrate, featuring a first and second dielectric layer with a conductive first portion and a bonding second portion, where the mean grain size of the second portion is smaller than the substrate, ensuring conductivity and reliable bonding without obstructing the conductive network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high purity alumina green sheets are used to manufacture electrostatic chuck with internal electrode structure, then plasma durability and surface roughness resistance are improved, but the bond between internal electrode layer and alumina layers becomes weak causing separation during processing
Solution Approach 1:
The patent applies different material compositions to different regions of the electrode layer. The first portion contains conductive material (Pd, Ag, or Cu) for electrical conductivity, while the second portion contains alumina powder with 99.9% or higher purity for strong bonding to the dielectric layers. This local differentiation allows the electrode layer to simultaneously achieve conductivity and bonding strength without compromising plasma durability.
2Strength
If alumina is added to internal electrode layer to strengthen bond, then bonding strength is improved, but the conductivity of internal electrode is reduced
Solution Approach 1:
The electrode layer is divided into two distinct portions: a first portion containing conductive material (Pd, Ag, or Cu) that ensures electrical conductivity, and a second portion containing alumina powder with 99.9% or higher purity that provides strong bonding to the dielectric layers. This segmentation allows each portion to optimize its specific function without compromising the other.
Solution Approach 2:
Different material compositions are assigned to different regions of the electrode layer. The conductive portion uses metallic materials for electron transport, while the bonding portion uses high-purity alumina for mechanical adhesion. This local quality differentiation resolves the contradiction between conductivity and bonding strength.
3Object-generated harmful factors
If conventional plasma cleaning is performed on electrostatic chuck surface, then residues are removed, but particles separate from ceramic surface causing erosion and increased surface roughness
Solution Approach 1:
The patent changes the material parameter of the dielectric substrate from conventional lower-purity alumina to high-purity alumina (99.9% or higher). This parameter change increases the material's resistance to plasma erosion and particle separation, allowing the surface to withstand repeated plasma cleaning cycles without degradation, thus maintaining surface integrity while enabling effective residue removal.
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 enhances the conductivity and bonding between the electrode layer and the ceramic substrate, improving plasma durability and maintaining electrostatic adhesion force, reducing gas leakage, and extending the chuck's operational lifespan.
Implementation Method 1
an electrostatic chuck capable of maintaining at a desired temperature an object to be processed that is adhered and held
Implementation Method 2
maintaining at a desired temperature an object to be processed that is adhered and held
Implementation Method 3
the electrode layer being integrally sintered with the ceramic dielectric substrate
Data Source
AI summary
To provide an electrostatic chuck, including: a ceramic dielectric substrate having a first major surface on which an object to be processed is mounted, and a second major surface on a side opposite the first major surface, the ceramic dielectric substrate being a polycrystalline ceramic sintered body; and an electrode layer interposed between the first major surface and the second major surface of the ceramic dielectric substrate, the electrode layer being integrally sintered with the ceramic dielectric substrate, and the electrode layer includes a first portion having conductivity, and a second portion that bonds the first dielectric layer and the second dielectric layer, and the mean grain size of crystals included in the second portion is smaller than the mean grain size of crystals included in the ceramic dielectric substrate.