Edge Ring Insteps and Oversized Lift-Pin Holes for Stable Positioning
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Solution Overview
Problem
Existing substrate processing systems face challenges in maintaining consistent and predictable positioning of edge rings due to variations in lift pin contact points caused by erosion and horizontal movement, leading to inconsistencies in plasma sheath control and substrate processing uniformity.
Innovation Solution
The implementation of edge rings with kinematic coupling features, such as 'V'-shaped grooves and recessed portions, to ensure precise alignment and positioning of edge rings relative to lift pins, along with collapsible edge ring assemblies that maintain radial alignment and vertical spacing, thereby stabilizing the edge rings during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional edge rings are used without kinematic coupling features, then manufacturing and installation are simpler, but positioning consistency and alignment precision deteriorate due to erosion and horizontal movement of lift pins
Solution Approach 1:
The edge ring incorporates a curved recessed portion that receives the lift pin, replacing a flat contact surface. This curvature allows the lift pin to maintain consistent contact with the edge ring even when the lift pin erodes or moves horizontally, as the curved surface compensates for variations in pin position and dimensions
Solution Approach 2:
The recessed portion acts as an intermediary feature between the lift pin and the edge ring body. It provides a dedicated receiving space that ensures proper alignment and contact, mediating the interaction between these components to achieve consistent positioning without requiring complex external alignment mechanisms
2Reliability
If edge rings are made fixed and stable, then positioning is more consistent, but adaptability to processing variations and plasma sheath control flexibility deteriorate
Solution Approach 1:
The edge ring is designed with moveable components including a collapsible assembly with multiple edge rings that can be raised and lowered relative to the substrate support. This dynamic configuration allows the system to adapt to different processing conditions and plasma sheath requirements while the kinematic coupling features ensure each position remains stable and consistent once established
3Loss of substance
If lift pins are allowed to erode naturally, then material loss occurs, but replacement and maintenance time increase
Solution Approach 1:
The recessed portion is designed with sufficient depth and dimensional tolerance to accommodate expected erosion of the lift pin over time. This pre-built tolerance cushion allows the lift pin to erode without compromising the positioning accuracy or functional performance, delaying the need for replacement and reducing maintenance frequency
Data Source
AI summary
An edge ring for a substrate support is provided. The edge ring includes an annular-shaped body and an instep. The annular-shaped body is sized and shaped to surround an upper portion of the substrate support. The annular-shaped body defines a first top surface, a second top surface, a lower surface, a radially inner surface, and a radially outer surface; and an instep. The instep is disposed at an upper radially inner portion of the annular-shaped body and transitions from the first top surface to the second top surface. The annular-shaped body includes a first hole configured for passage of a first lift pin, the first hole being oversized to prevent the annular-shaped body from contacting the first lift pin.