Radially Aligned Pad Design for Electrostatic Chuck Thermal Management
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Solution Overview
Problem
Conventional electrostatic chucks experience issues with non-uniform chucking force and excessive heat transfer, leading to substrate deformation, particle generation, and damage during processing, which results in wear and breakage of both the substrate and the chuck.
Innovation Solution
The electrostatic chuck assembly features a wafer spacing mask with radially aligned elongated features and gas passages on its frontside surface, which minimizes substrate-chuck contact area and regulates heat transfer by controlling the flow of backside gas, thereby reducing particle generation and stress on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrostatic chucks use a flat contact surface, then substrate chucking is achieved, but non-uniform chucking force causes substrate deformation and particle generation
Solution Approach 1:
The flat contact surface is segmented into multiple discrete contact pads arranged in a specific pattern. This segmentation allows different regions to provide different levels of support, creating uniform distributed pressure across the substrate while preventing deformation and particle generation that occur with conventional flat surfaces.
Solution Approach 2:
Different regions of the contact surface are given different properties through the pad pattern design. The contact pads are strategically positioned to provide localized support where needed, creating non-uniform local contact that results in uniform overall pressure distribution, thereby maintaining substrate flatness during chucking.
2Force
If electrostatic chuck generates strong electrostatic field, then substrate clamping force is sufficient, but excessive heat transfer occurs causing substrate and chuck damage
Solution Approach 1:
The contact surface is divided into discrete pads rather than a continuous flat surface. This segmentation reduces the total contact area between substrate and chuck, thereby reducing heat transfer while maintaining sufficient electrostatic clamping force through the electric field acting on the entire substrate area.
Solution Approach 2:
The pad structure acts as an intermediary between the substrate and the chuck body. It provides mechanical support and electrical contact while limiting thermal contact, serving as a mediator that allows force transmission but restricts heat transfer to prevent damage.
3Reliability
If substrate contact area with chuck is large, then stable chucking is achieved, but heat transfer exceeds physical limitations causing cracks and breakage
Solution Approach 1:
The contact area is segmented into multiple small pads rather than one large continuous area. This provides stable chucking through distributed contact points while limiting the heat transfer area at each contact point, preventing thermal stress that would cause cracks or breakage.
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 reduces wear and damage to both the substrate and the chuck by maintaining thermal uniformity and minimizing stress, enhancing operational reliability and longevity.
Implementation Method 1
regulates heat transfer by controlling the flow of backside gas
Implementation Method 2
an electrostatic clamping field can be generated
Implementation Method 3
Semi-conductive ceramic materials, such as aluminum nitride, boron nitride, or aluminum oxide doped with a metal oxide, for example, may be used to enable Johnsen-Rahbek or non-Coulombic electrostatic clamping fields to be generated
Data Source
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AI summary
An electrostatic chuck assembly and processing chamber having the same are disclosed herein. In one embodiment, an electrostatic chuck assembly is provided that includes a body having an outer edge connecting a frontside surface and a backside surface. The body has chucking electrodes disposed therein. A wafer spacing mask is formed on the frontside surface of the body. The wafer spacing mask has a plurality of elongated features. The elongated features have long axes that are radial aligned from the center to the outer edge. The wafer spacing mask has a plurality of radially aligned gas passages defined between the elongated features.