Ceramic Multi-Plate Electrostatic Chucks for RF and Thermal Stability
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Solution Overview
Problem
Existing electrostatic chucks face issues with high-voltage breakdown, cracking of ceramic coatings, and thermal mismatch due to differing coefficients of thermal expansion between ceramic top plates and metal baseplates, limiting operational temperature ranges and RF voltage control.
Innovation Solution
The use of multi-plate electrostatic chucks with both the top plate and baseplate made of ceramic materials, minimizing thermal expansion differences and eliminating high-voltage breakdown and cracking, while allowing for increased RF voltage handling and improved temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a metal baseplate is used with a ceramic top plate, then electrical conductivity and RF control are improved, but thermal mismatch and cracking occur due to differing coefficients of thermal expansion
Solution Approach 1:
The baseplate is constructed from a single piece of ceramic material matching the top plate material, creating thermal homogeneity throughout the electrostatic chuck assembly. This eliminates thermal mismatch and cracking while maintaining structural integrity and RF control capabilities through the inherent electrical properties of the ceramic material.
2Reliability
If a ceramic top plate is used, then high-voltage breakdown is eliminated, but thermal expansion mismatch with metal baseplate causes cracking
Solution Approach 1:
Both the top plate and baseplate are made from the same or compatible ceramic materials with matched thermal expansion coefficients. This material homogeneity prevents differential thermal expansion, eliminating the root cause of cracking while preserving the high-voltage stability provided by the ceramic top plate.
3Adaptability or versatility
If operational temperature range is expanded, then process versatility is improved, but thermal mismatch between ceramic and metal components increases
Solution Approach 1:
The all-ceramic construction with matched thermal expansion properties enables the electrostatic chuck to withstand expanded operational temperature ranges without suffering from thermal mismatch. The homogeneous ceramic material composition throughout the assembly allows uniform thermal response, maintaining reliability across broader temperature conditions.
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 ceramic-based multi-plate design enhances operational temperature ranges and RF voltage control, reducing the risk of arcing and misalignment, and providing improved thermal stability and RF control across the substrate.
Implementation Method 1
A substrate is arranged on an electrostatic chuck (ESC) in a substrate processing system and a thin film on the substrate is etched
Implementation Method 2
The intermediate layer bonds the top plate to the baseplate
Data Source
AI summary
An electrostatic chuck for a substrate processing system is provided. The electrostatic chuck includes: a top plate configured to electrostatically clamp to a substrate and formed of ceramic; an intermediate layer disposed below the top plate; and a baseplate disposed below the intermediate layer and formed of ceramic. The intermediate layer bonds the top plate to the baseplate.