Electrostatic Chuck Sidewall Ground Mesh for Parasitic Plasma Control
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Solution Overview
Problem
Existing plasma processing chambers face issues with non-uniformity and asymmetry in the RF return path, leading to parasitic plasma formation and power loss due to the lack of a proper ground along the vertical wall of the substrate support.
Innovation Solution
A substrate support assembly with a vertical ground electrode mesh disposed along the side surface of the substrate support, which is electrically coupled to the RF return path, providing a proper ground and reducing parasitic plasma formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional substrate support without vertical ground electrode is used, then the device complexity is reduced, but parasitic plasma formation increases and RF return path stability deteriorates
Solution Approach 1:
The ground electrode is segmented into multiple sections along the vertical wall of the substrate support, with each segment electrically isolated from others. This segmentation allows the ground potential to be distributed uniformly along the vertical surface, preventing localized plasma formation while maintaining overall RF return path stability without requiring a single complex continuous ground structure
Solution Approach 2:
A dielectric material is introduced as an intermediary between the vertical ground electrode segments and the plasma environment. This dielectric layer prevents direct plasma contact with the ground electrode segments while allowing the segments to establish the necessary ground potential, thereby suppressing parasitic plasma formation without requiring the ground electrodes to extend directly into the plasma region
2Loss of energy
If no vertical ground electrode is provided, then the manufacturing process is simpler, but power loss increases due to parasitic plasma
Solution Approach 1:
The vertical ground electrode segments are pre-positioned and electrically connected to the RF return path before final assembly of the substrate support. This preliminary establishment of ground connections ensures proper RF current return paths are in place before operation, preventing parasitic plasma formation and associated power losses without requiring complex post-assembly modifications
Solution Approach 2:
The vertical ground electrode segments automatically establish the necessary ground potential along the substrate support vertical wall through their connection to the RF return path. This self-adjusting ground system suppresses parasitic plasma formation without requiring external control systems or additional active components, thereby reducing power loss while maintaining manufacturing simplicity
3Reliability
If the ground electrode extends to the outer surface, then the ground coverage is improved, but the structural integrity and sealing of the substrate support deteriorates
Solution Approach 1:
The ground electrode segments are positioned locally along the vertical wall interior surface rather than extending to the outer surface. This local placement provides sufficient ground coverage to suppress parasitic plasma where it most commonly forms, while preserving the structural integrity and sealing properties of the substrate support outer wall
Solution Approach 2:
The vertical ground electrode segments are nested within the substrate support structure, positioned in the interior space along the vertical wall. This nested configuration allows the ground electrodes to provide comprehensive ground coverage for plasma suppression while remaining contained within the substrate support structure, thereby maintaining structural strength and sealing without requiring external ground electrode extensions
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 implementation of the vertical ground electrode mesh enhances the stability of the RF return path, reduces parasitic plasma, and minimizes power loss, thereby improving the uniformity and efficiency of plasma processing.
Implementation Method 1
A substrate support assembly with a vertical ground electrode mesh disposed along the side surface of the substrate support, which is electrically coupled to the RF return path
Implementation Method 2
sintering an aluminum nitride (AlN) or aluminum oxide body having a heater, an RF electrode mesh and a high voltage (HV) ESC electrode mesh
Data Source
AI summary
Disclosed herein is a substrate support assembly having a ground electrode mesh disposed therein along a side surface of the substrate support assembly. The substrate support assembly has a body. The body has an outer top surface, an outer side surface and an outer bottom surface enclosing an interior of the body. The body has a ground electrode mesh disposed in the interior of the body and adjacent the outer side surface, wherein the ground electrode does not extend through to the outer top surface or the outer side surface.