Wafer Placement Table Layout for Heat Dissipation and Discharge Control
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Solution Overview
Problem
Existing wafer placement tables suffer from hot spots and electrical discharge issues due to insufficient heat dissipation and potential gradients in gas supply passages, impairing wafer soaking performance and potentially causing charring or particle generation.
Innovation Solution
A wafer placement table design with a ceramic plate, electrically conductive plate, and gas intermediate passages embedded in an electrically conductive bonding layer, where the number of gas introduction passages is fewer than gas supply passages, ensuring equal potential across the gas intermediate passage surfaces to prevent electrical discharge and improve heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gas supply passages pass through the cooling plate in the up and down direction, then gas can be supplied to the wafer, but hot spots are formed due to insufficient heat dissipation
Solution Approach 1:
The patent introduces a gas intermediate passage that extends in the horizontal direction (parallel to wafer placement surface) rather than only in the vertical direction. This dimensional change allows gas to be distributed through multiple gas supply passages without requiring each to pass independently through the cooling plate, thereby improving heat dissipation while maintaining gas supply function.
2Temperature
If a gas intermediate passage is provided parallel to the wafer placement surface, then soaking performance is improved, but electrical discharge may occur due to potential gradient
Solution Approach 1:
The patent introduces an electrically conductive bonding layer as an intermediary between the ceramic plate and the electrically conductive cooling plate. This bonding layer electrically connects the two components, equalizing their potentials and preventing electrical discharge in the gas intermediate passage while allowing the passage to extend horizontally for improved soaking performance.
3Temperature
If the number of gas introduction passages is reduced, then soaking performance improves, but manufacturing complexity may increase
Solution Approach 1:
The patent segments the gas supply system into one or more gas introduction passages that extend through the cooling plate, a horizontal gas intermediate passage, and multiple gas supply passages. This segmentation allows reduction in the number of vertical passages through the cooling plate while maintaining effective gas distribution, thereby improving soaking performance without excessive manufacturing complexity.
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 design enhances wafer soaking performance by preventing electrical discharge and improving heat transfer efficiency, while allowing for easier manufacturing and reduced electrical interference.
Implementation Method 1
the electrically conductive bonding layer and the electrically conductive plate are in contact with each other and have the same potential. Therefore, no potential gradient occurs between the upper and lower sides of the gas intermediate passage, so electrical discharge in the gas intermediate passage is prevented
Implementation Method 2
Gas (for example, heat transfer gas, such as He gas) introduced from an outside into the gas supply passages is supplied to the lower surface of a wafer through the gas supply passages
Implementation Method 3
a metal cooling plate bonded to the lower surface of the ceramic plate... parts of a refrigerant flow channel of the cooling plate
Data Source
AI summary
A wafer placement table includes: a ceramic plate having a wafer placement surface on its upper surface and incorporating an electrode; an electrically conductive plate provided on a lower surface side of the ceramic plate; an electrically conductive bonding layer that bonds the ceramic plate with the electrically conductive plate; a gas intermediate passage embedded in the electrically conductive bonding layer or provided at an interface between the electrically conductive bonding layer and the electrically conductive plate; a plurality of gas supply passages extending from the gas intermediate passage through the electrically conductive bonding layer and the ceramic plate to the wafer placement surface; and a gas introduction passage provided so as to extend through the electrically conductive plate and communicate with the gas intermediate passage, the number of the gas introduction passages being smaller than the number of the gas supply passages communicating with the gas intermediate passage.