Electrostatic Chuck Mesa Layout for Uniform Substrate Cooling
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Solution Overview
Problem
Substrate mesas that are too sparse in electrostatic chucks (ESCs) can lead to overheating of substrates during processing.
Innovation Solution
The implementation of an electrostatic chuck (ESC) with a top surface and a plurality of mesas extending upward, where the upper surface of the mesas defines a substrate support surface, and the ESC includes backside gas openings and chucking electrodes to effectively manage substrate cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the substrate support surface area is increased to improve cooling efficiency, then the cooling performance improves, but the device complexity increases
Solution Approach 1:
The substrate support surface is segmented into multiple discrete mesas rather than a continuous surface. This segmentation allows the cooling function to be distributed across multiple independent contact points, achieving effective cooling while maintaining structural simplicity. Each mesa acts as an independent cooling element, and their collective effect provides sufficient thermal management without requiring a complex continuous cooling surface.
Solution Approach 2:
The cooling function is concentrated at specific local points (mesa locations) rather than distributed uniformly across the entire substrate support surface. The mesas provide localized thermal contact points that are strategically positioned to achieve effective substrate cooling. This local quality approach allows efficient cooling with minimal structural complexity by focusing cooling capability at discrete locations rather than requiring comprehensive surface coverage.
2Temperature
If the mesa density is increased to improve substrate contact and cooling, then cooling efficiency improves, but the gas flow distribution becomes more difficult
Solution Approach 1:
The gas delivery system is segmented into multiple discrete backside gas openings that correspond to the mesa arrangement. This segmentation allows gas flow to be distributed to specific regions where mesas are located, ensuring proper cooling function without requiring complex gas distribution networks. The segmented gas opening configuration simplifies the overall design by matching the modular mesa structure.
Solution Approach 2:
The mesas serve multiple functions simultaneously: they provide substrate contact points for mechanical support, create cooling pathways for thermal management, and define regions for gas flow distribution. This multi-functionality eliminates the need for separate structures for each function, simplifying the overall device design while achieving effective cooling and gas distribution.
3Temperature
If the total surface area of mesas is increased to prevent overheating, then substrate temperature control improves, but the chucking force distribution becomes less uniform
Solution Approach 1:
The mesa structure employs asymmetric design where the top surface area of mesas is optimized for cooling contact while the bottom surface area provides adequate chucking contact. This asymmetric configuration allows the mesas to fulfill dual roles: providing sufficient cooling surface area on the substrate-facing side while maintaining appropriate mechanical contact on the chucking side. The asymmetric geometry resolves the contradiction between cooling efficiency and force distribution by optimizing each surface for its primary function.
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 enhanced mesas configuration increases the cooling efficiency of substrates by providing a larger contact area and ensuring uniform distribution of backside gases, thereby preventing overheating.
Implementation Method 1
an electrostatic chuck (ESC) having one or more electrodes that can be electrically biased to hold a substrate to the substrate support surface
Implementation Method 2
backside cooling gas may be delivered to the substrate
Implementation Method 3
backside cooling gas may be delivered to the substrate
Data Source
AI summary
Embodiments of substrate supports having electrostatic chucks (ESCs) for use in substrate process chambers are provided herein. In some embodiments, a substrate support includes: an electrostatic chuck (ESC) having a top surface and a plurality of mesas extending upward from the top surface, wherein an upper surface of the plurality of mesas define a substrate support surface, wherein a total surface area of the substrate support surface is about 18 to about 40 percent a total surface area of the upper surface, and wherein the ESC includes a plurality of backside gas openings extending through the ESC; and one or more chucking electrodes disposed in the ESC.