Dielectric Cooling Plate Assembly for Thermal-Cycling-Resistant Chucks
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Solution Overview
Problem
Conventional electrostatic chucks degrade due to thermal cycling stress, fatigue, and creep, limiting their suitability for high temperature and cryogenic applications, and they are unsuitable for processes involving high plasma power or high surface temperatures.
Innovation Solution
A substrate support assembly comprising a puck plate and a dielectric cooling plate, both made of ceramic materials with similar thermal expansion coefficients, bonded together using various methods, allowing for efficient heat dissipation and minimizing degradation from thermal cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal cooling plates coated with dielectric are used, then cooling efficiency is improved, but coating quality degrades due to thermal cycling stress, fatigue, and creep
Solution Approach 1:
The patent uses a composite structure consisting of a metal cooling plate bonded to a dielectric layer. The metal plate provides efficient thermal conduction for cooling, while the dielectric layer provides electrical insulation. This composite material approach allows the system to achieve both good cooling efficiency and reliable performance under thermal cycling conditions, as each material performs its optimal function without the drawbacks of using a single material for both purposes.
2Strength
If organic bonding material is used to bond ceramic body to metal cooling plate, then bonding is achieved, but power dissipation is limited for high temperature processes
Solution Approach 1:
The patent changes the bonding method from organic bonding material to inorganic bonding materials such as glass frit or ceramic bonding agents. This parameter change in the bonding material composition allows the assembly to withstand higher temperatures and greater power dissipation. The inorganic bonding materials maintain their structural integrity and bonding strength at elevated temperatures where organic materials would decompose or fail, thereby enabling high temperature etching processes.
3Stability of the object's composition
If ceramics with low thermal expansion coefficient are used, then thermal stability at high temperature is improved, but stress arises due to difference in coefficients of thermal expansion with metal
Solution Approach 1:
The patent introduces an intermediary bonding layer (glass frit or ceramic bonding agent) between the ceramic electrostatic chuck and the metal cooling plate. This intermediary layer acts as a stress buffer that accommodates the difference in thermal expansion coefficients between the ceramic and metal materials. During thermal cycling, the bonding layer flexes and absorbs the differential expansion/contraction stresses, preventing stress concentration and potential failure at the interface, thereby allowing the system to maintain thermal stability while reducing thermal stress.
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 assembly supports high temperature and low temperature applications without degrading due to stress, fatigue, or creep, enhancing power dissipation and maintaining substrate integrity during processes like dielectric film etching.
Implementation Method 1
The substrate support assembly includes a ceramic cooling plate, which may be bonded to the electrostatic chuck... the ceramic cooling plate... enhancing power dissipation for high temperature processes
Implementation Method 2
The dielectric cooling plate includes one or more channels for a coolant to flow therethrough
Data Source
AI summary
A substrate support assembly includes a first puck plate including one or more first functional elements, and a dielectric cooling plate is bonded to the first puck plate. The dielectric cooling plate includes one or more first channels for a coolant to flow therethrough, and one or more second channels for a gas to flow therethrough.