Moveable Edge Ring Geometry for Etch Uniformity and Plasma Confinement
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Solution Overview
Problem
Substrate processing systems face challenges in achieving uniform etch rates and preventing plasma erosion of substrate supports due to fixed edge ring configurations, which can lead to variations in gas flow patterns and substrate support integrity.
Innovation Solution
The implementation of a moveable edge ring system that can be raised and lowered via lift pins, allowing for tuning and replacement, and featuring a labyrinthine interface with guide features to prevent plasma leakage and facilitate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed edge ring configuration is used, then the substrate support structure is simple and stable, but etch uniformity deteriorates and plasma erosion increases
Solution Approach 1:
The edge ring is made moveable through lift pins that enable vertical adjustment of the edge ring relative to the substrate support. This dynamic configuration allows the edge ring to be raised or lowered to optimize etch uniformity while protecting against plasma erosion, resolving the contradiction between maintaining simple stable structure and achieving precise etch control.
2Manufacturing precision
If the edge ring is made moveable via lift pins, then etch uniformity improves, but device complexity increases
Solution Approach 1:
The lift pin mechanism provides controlled mobility to the edge ring, enabling vertical positioning adjustments that improve etch uniformity. The mechanism balances the added complexity of movability with the performance benefits of adjustable edge ring geometry.
Solution Approach 2:
The moveable edge ring allows changing the vertical position parameter of the edge ring relative to the substrate support. This parameter adjustment optimizes the pocket depth and gas flow patterns, thereby improving etch uniformity while managing the complexity through controlled parameter variation.
3Reliability
If the edge ring is lowered to increase pocket depth, then plasma confinement improves, but access for maintenance becomes difficult
Solution Approach 1:
The lift pins enable the edge ring to be dynamically raised or lowered. During operation, the edge ring can be lowered to increase pocket depth for improved plasma confinement. During maintenance, the edge ring can be raised to improve accessibility, thus resolving the contradiction between plasma confinement and maintenance ease.
Data Source
AI summary
An edge ring is configured to be raised and lowered relative to a substrate support, via one or more lift pins, in a substrate processing system. The edge ring is further configured to interface with a guide feature extending upward from a bottom ring and/or a middle ring of the substrate support during tuning of the edge ring. The edge ring includes an upper surface, an annular inner diameter, an annular outer diameter, a lower surface, and an annular groove arranged in the lower surface of the edge ring to interface with the guide feature. Walls of the annular groove are substantially vertical.