Electrostatic Chuck Assembly With Uniform Fastening for 500°C Processing
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Solution Overview
Problem
Electrostatic chucks used in substrate processing fail at high temperatures due to issues such as de-chucking, plasma erosion, and bond reliability, limiting their effectiveness in high-temperature processes.
Innovation Solution
An electrostatic chuck assembly with a puck composed of an insulative upper puck plate and a lower puck plate bonded by a metal bond, featuring evenly distributed fasteners to ensure uniform fastening force, coupled with a cooling plate for controlled heat transfer, and optionally including a spring-loaded heat sink for enhanced thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional electrostatic chucks are used in high temperature processes, then substrate processing can be performed, but the chuck components fail due to de-chucking, plasma erosion, and bond reliability issues at temperatures above 120°C
Solution Approach 1:
The chuck is divided into separate modular components including an upper chucking surface, lower chucking surface, and side wall portions that can be independently selected and replaced. This segmentation allows each component to be optimized for specific temperature and chemical resistance requirements, improving overall reliability at high temperatures
Solution Approach 2:
The chuck utilizes composite construction with different materials for different components - such as ceramic materials for the upper chucking surface that can withstand high temperatures, and metal or other materials for the lower surface and side walls. This composite approach enables the chuck to maintain reliability across the full temperature range by selecting materials with appropriate thermal and chemical properties for each location
2Stress or pressure
If fasteners are unevenly distributed on the cooling plate, then assembly is simpler, but non-uniform fastening force causes poor thermal contact and ineffective heat transfer
Solution Approach 1:
The fastener holes are positioned at different radial distances from the center of the cooling plate, creating an asymmetric distribution pattern. This asymmetric placement allows the fasteners to apply force at optimal locations that compensate for thermal expansion differences and structural variations, achieving more uniform fastening force and thermal contact across the interface
Solution Approach 2:
Different regions of the cooling plate have fasteners positioned according to local requirements - with specific holes at different distances from the center to provide appropriate fastening force distribution. This local optimization ensures uniform thermal contact where needed while maintaining structural integrity, improving heat transfer effectiveness
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
Facilitates uniform heat transfer and temperature control, allowing the chuck to operate effectively at temperatures up to 500°C, reducing thermo-mechanical stresses and enhancing durability in high-temperature environments.
Implementation Method 1
Electrostatic chucks typically include one or more electrodes embedded within a unitary chuck body which includes a dielectric or semi-conductive ceramic material across which an electrostatic clamping field can be generated
Implementation Method 2
an electrostatic chuck assembly that includes a puck with an electrically insulative upper puck plate comprising one or more heating elements
Implementation Method 3
a cooling plate coupled to the puck by the fasteners
Data Source
AI summary
An electrostatic chuck assembly includes a puck and a cooling plate. The puck includes an electrically insulative upper puck plate comprising one or more heating elements and one or more electrodes to electrostatically secure a substrate and further includes a lower puck plate bonded to the upper puck plate by a metal bond, the lower puck plate comprising a plurality of features distributed over a bottom side of the lower puck plate at a plurality of different distances from a center of the lower puck plate, wherein each of the plurality of features accommodates one of a plurality of fasteners. The cooling plate is coupled to the puck by the plurality of fasteners, wherein the plurality of fasteners each apply an approximately equal fastening force to couple the cooling plate to the puck.