Electrostatic Chuck Metal Matrix Composite Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrostatic chucks face challenges in operating at high temperatures and wide temperature ranges in high vacuum environments due to thermo-mechanical stresses from differences in thermal expansion coefficients between ceramic and metal components, leading to potential fracture and vacuum seal failures, and inefficiencies in RF power transmission over a wide frequency range.
Innovation Solution
The electrostatic chuck assembly incorporates a support base and puck with electrically conductive metal matrix composite chucking electrodes and a dielectric layer, along with a cooling plate and o-rings, to minimize thermo-mechanical stresses and optimize RF power coupling, using a bellows assembly for vacuum sealing and a detachable design for easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If metal components are attached to or embedded within the ceramic chuck body, then the electrostatic chuck can provide heating and cooling functions and route power to electrodes, but differences in thermal expansion coefficients between ceramic and metal cause thermo-mechanical stresses that can fracture or chip the ceramic during thermal cycling
Solution Approach 1:
The patent employs a composite structure consisting of a ceramic chuck body (e.g., aluminum oxide, aluminum nitride, or boron nitride) combined with metal components (electrodes, heating elements, gas channels, coolant channels). This composite design allows the integration of multiple functions while managing the inherent CTE mismatch between dissimilar materials through careful material selection and structural design.
Solution Approach 2:
The patent applies local quality by providing thermal management and electrical connections only in specific regions where needed, rather than uniformly throughout the chuck body. Gas channels and coolant channels are strategically positioned to provide heating and cooling where required, and electrodes are placed only in areas needing electrical connection, reducing overall stress exposure.
2Reliability
If the ceramic chuck body is made thicker to compensate for thermo-mechanical stresses, then fracture resistance improves, but manufacturing cost increases
Solution Approach 1:
By using composite materials with carefully selected CTE values, the patent achieves adequate fracture resistance without requiring excessive thickness. The combination of ceramic and metal components allows stress distribution and compensation that enables thinner, more cost-effective designs.
Solution Approach 2:
The patent changes material parameters (selecting specific ceramic and metal combinations with compatible CTE values) to optimize the balance between fracture resistance and thickness, avoiding the need for uniformly thick designs that increase cost.
3Reliability
If polymer o-rings are used to seal feedthroughs, then vacuum sealing is achieved, but the o-rings lose compliance and resilience at high temperatures leading to seal failure
Solution Approach 1:
The patent uses flexible sealing elements (o-rings) to create vacuum seals at feedthrough interfaces. These flexible components conform to mating surfaces to maintain sealing integrity while accommodating thermal expansion and manufacturing tolerances.
Solution Approach 2:
The patent addresses high-temperature seal failure by selecting o-ring materials with appropriate temperature ratings and potentially using alternative sealing approaches (such as metal seals or different polymer compositions) that maintain compliance and resilience at elevated temperatures.
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
This design enables a cost-effective electrostatic chuck to operate reliably over wide temperature ranges in high vacuum environments while efficiently coupling RF power over a broad frequency range, reducing thermo-mechanical stresses and maintaining vacuum integrity.
Implementation Method 1
the one or more chucking electrodes comprise an electrically conductive metal matrix composite material
Implementation Method 2
a dielectric layer disposed on the frontside surface and covering the one or more chucking electrodes
Implementation Method 3
cooling plate and o-rings, to minimize thermo-mechanical stresses
Implementation Method 4
vacuum sealing and a detachable design for easy replacement
Data Source
AI summary
Embodiments of the present invention provide a cost effective electrostatic chuck assembly capable of operating over a wide temperature range in an ultra-high vacuum environment while minimizing thermo-mechanical stresses within the electrostatic chuck assembly. In one embodiment, the electrostatic chuck assembly includes a dielectric body having chucking electrodes which comprise a metal matrix composite material with a coefficient of thermal expansion (CTE) that is matched to the CTE of the dielectric body.