Electrostatic Chuck Coolant Layout for Wafer Edge Temperature Uniformity
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Solution Overview
Problem
Existing electrostatic chucks fail to achieve uniform in-plane temperature distribution of wafers during processes like etching, particularly in the outer circumferential parts, due to inadequate routing of coolant flow paths.
Innovation Solution
The coolant flow path is designed with varying cooling performance between the first part immediately below the wafer's edge and the second part on its outer side, with higher cooling performance in the first part to reduce temperature increase and maintain uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the coolant flow path is extended to the second part on the outer side, then the temperature increase in the outer circumferential part of the wafer is reduced, but the members arranged on the further outer side may be cooled down more than necessary
Solution Approach 1:
The coolant flow path is designed with varying cooling performance between the first part and second part. Specifically, the flow path is configured to provide higher cooling performance to the first part (overlapped with wafer outer circumferential edge) and lower cooling performance to the second part (further outer circumferential side). This local differentiation ensures that the wafer receives adequate cooling to maintain temperature uniformity, while outer members receive only the cooling they actually need, avoiding excessive energy loss.
2Device complexity
If the coolant flow path is formed only in the first part overlapped with the wafer, then the structure is simpler, but the temperature increase in the outer circumferential part of the wafer cannot be sufficiently reduced
Solution Approach 1:
The base plate is segmented into two distinct regions: a first part that is overlapped with the outer circumferential edge of the wafer, and a second part located on the further outer circumferential side. The coolant flow path is separately formed in each region with different cooling performances. This segmentation allows the system to achieve effective temperature control across the entire wafer surface while maintaining a relatively simple overall structure, as each segment serves its specific thermal management 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
This configuration effectively reduces temperature non-uniformity in the outer circumferential part of the wafer, preventing unnecessary cooling of adjacent components and achieving a more uniform in-plane temperature distribution.
Implementation Method 1
Heat from the wafer is transferred to the coolant via the dielectric substrate and the base plate, and then the heat is exhausted to the outside together with the coolant
Implementation Method 2
a coolant flow path through which a coolant flows is formed inside the base plate. Heat from the wafer is transferred to the coolant
Implementation Method 3
When a voltage is applied to the attraction electrode, an electrostatic force is generated, and the wafer placed on the dielectric substrate is attracted and held
Data Source
AI summary
An electrostatic chuck includes a dielectric substrate including a surface serving as a placement surface, and a base plate which is joined to the dielectric substrate and which has formed therein a coolant flow path through which a coolant flows. In top view, the base plate includes a first part that is a part overlapped with an edge on an outer circumferential side of the surface, and a second part P2 that is a part on the further outer circumferential side relative to the first part P1, and the coolant flow path is formed in each of the first part P1 and the second part. The coolant flow path is formed in a manner that a cooling performance for the first part is set to be higher than a cooling performance for the second part.