Stepped Middle and Bottom Rings for Etch Uniformity Control
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Solution Overview
Problem
Substrate processing systems face challenges in maintaining etch uniformity and preventing plasma leakage due to the fixed geometry of edge rings, which can lead to erosion and variations in etch rates during substrate processing.
Innovation Solution
The implementation of moveable edge rings supported by bottom and middle rings, allowing for adjustable height and geometry to control etch uniformity and prevent plasma leakage through a labyrinthine interface design with chamfered corners and guide channels, enabling precise control and minimization of plasma exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed geometry edge ring is used, then the structure is simple and easy to manufacture, but etch uniformity deteriorates and plasma leakage occurs due to erosion during processing
Solution Approach 1:
The edge ring is made moveable rather than fixed, allowing it to be adjusted vertically to compensate for erosion during substrate processing. The bottom ring includes guide channels that receive lift pins to raise and lower the edge ring, transforming it from a static component to a dynamic one that can maintain optimal positioning throughout its service life, thereby preserving etch uniformity despite erosion.
Solution Approach 2:
The vertical position of the edge ring is changed as a parameter to compensate for erosion. By adjusting the height of the edge ring relative to the substrate support, the system maintains the intended geometry and etch uniformity over time, counteracting the degradation that would otherwise occur with a fixed structure.
2Reliability
If an edge ring is made moveable to compensate for erosion, then etch uniformity is maintained, but the device complexity increases due to additional components
Solution Approach 1:
The support structure is segmented into multiple functional components: a bottom ring with guide channels, lift pins for vertical adjustment, and a labyrinthine interface between the edge ring and substrate support. This segmentation allows each component to perform its specific function while collectively providing reliable plasma leakage prevention through the complex, multi-path interface design.
Solution Approach 2:
The labyrinthine interface acts as an intermediary structure between the edge ring and substrate support, creating a complex, multi-path barrier that effectively prevents plasma leakage. This intermediary design adds reliability by providing multiple pathways that plasma would need to penetrate, thereby enhancing sealing without requiring the entire edge ring assembly to be overly complex.
3Manufacturing precision
If the edge ring geometry is adjusted to control etch uniformity, then processing quality improves, but the manufacturing complexity increases
Solution Approach 1:
Rather than manufacturing multiple edge ring geometries, the system uses a single edge ring that can be dynamically adjusted vertically during its service life. The guide channels and lift pins enable this adjustment, allowing the same component to maintain optimal etch uniformity throughout its operational lifespan without requiring complex manufacturing of multiple geometric variants.
Data Source
AI summary
A middle ring configured to be arranged on a bottom ring and to support a moveable edge ring and further configured to be raised and lowered relative to a substrate support includes an upper surface that is stepped, an annular inner diameter, an annular outer diameter, a lower surface, a guide feature in the upper surface defining the annular outer diameter, an inner annular rim in the upper surface defining the annular inner diameter, and a groove defined in the upper surface between the guide feature and the inner annular rim.