Wafer Placement Table Conductive Gas Path for Plug-End Discharge
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Solution Overview
Problem
Existing wafer placement tables experience discharge issues around the base plate-side end of the electrically insulating gas passage plug, despite the use of electrically insulating porous portions.
Innovation Solution
Incorporating an electrically conductive gas passage part within the gas introduction passage, which is in contact with the bottom surface of an electrically insulating gas passage plug and electrically continuous with an electrically conductive plate, to reduce potential differences and discharge occurrences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically insulating porous portion is used in the gas passage, then discharge due to plasma is suppressed, but discharge occurs around the base plate-side end of the gas passage plug
Solution Approach 1:
An electrically conductive portion is introduced as an intermediary element between the electrically insulating porous portion and the electrically conductive base plate. This intermediary conductive portion extends into the porous portion and provides a continuous electrical path to the base plate, preventing potential difference accumulation at the plug end while maintaining the discharge suppression function of the porous structure
Solution Approach 2:
The gas passage plug is constructed as a composite structure combining electrically insulating porous material and electrically conductive material. The conductive portion is embedded within or extends into the insulating porous portion, creating a hybrid structure that simultaneously achieves electrical insulation for plasma discharge suppression and electrical conduction for potential equalization at the base plate interface
2Temperature
If gas pressure is increased to improve heat transfer, then heat transfer efficiency improves, but discharge occurs more frequently
Solution Approach 1:
The electrically conductive portion creates an equipotential path from the base plate through the gas passage plug, eliminating potential differences that would otherwise increase with higher gas pressure. This ensures that even when gas pressure is increased for better heat transfer, discharge does not occur because the electrical potential is equalized throughout the plug structure
3Reliability
If an electrically conductive gas passage part is added, then discharge is reduced, but device complexity increases
Solution Approach 1:
The electrically conductive portion is merged with the gas passage plug structure itself, rather than being a separate external component. The conductive material is integrated within the plug body or extends as part of the plug structure, combining the gas passage function and electrical conduction function into a single integrated component, thereby minimizing device 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
This configuration effectively minimizes discharge around the electrically conductive plate-side end of the gas passage plug, allowing for increased gas pressure and improved heat transfer efficiency while maintaining easy manufacturing and contact with the plug.
Implementation Method 1
the electrically conductive gas passage part is electrically continuous with the electrically conductive plate
Implementation Method 2
Gas supplied to the gas introduction passage passes through the second porous portion and the first porous portion and flows into the space between the wafer placement surface and a wafer
Data Source
AI summary
A wafer placement table includes a ceramic plate having a wafer placement surface on its top surface and incorporating an electrode; an electrically conductive plate joined to a bottom surface of the ceramic plate; a ceramic plate penetrating part extending through the ceramic plate; an electrically insulating gas passage plug provided in the ceramic plate penetrating part and that allows gas to pass inside; a gas introduction passage provided at least inside the electrically conductive plate and communicating with the ceramic plate penetrating part; and an electrically conductive gas passage part provided in the gas introduction passage, being in contact with a bottom surface of the electrically insulating gas passage plug, being electrically continuous with the electrically conductive plate, and that allows gas to pass inside.