S-Shaped Plasma Confinement Ring for Uniform Density and Wear
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Solution Overview
Problem
Existing confinement rings in semiconductor processing chambers face challenges in maintaining uniform plasma density and mechanical strength while requiring frequent replacements due to uneven wear, which affects plasma confinement and increases operational costs.
Innovation Solution
The design of an S-shaped confinement ring with a tapered slot geometry and sloped surfaces that extends the usage life by evenly distributing wear and optimizing plasma confinement without altering existing hardware components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional C-shaped confinement rings are used, then the structure is simple and easy to manufacture, but the plasma density uniformity is poor and wear is uneven leading to frequent replacements
Solution Approach 1:
The confinement ring transitions from a symmetric C-shape to an asymmetric S-shape with different vertical sections. The first vertical section has a greater height than the second vertical section, creating asymmetric plasma confinement that improves radial plasma density uniformity while maintaining structural integrity and reducing uneven wear
Solution Approach 2:
The design adds vertical dimension variation to the confinement ring structure by creating two distinct vertical sections with different heights. This dimensional change allows the ring to optimize plasma confinement in both inner and outer regions simultaneously, improving overall plasma density uniformity without significantly increasing manufacturing complexity
2Reliability
If the confinement ring structure is modified to improve plasma uniformity, then plasma density uniformity improves, but the mechanical strength and lifetime may be compromised
Solution Approach 1:
The confinement ring employs local quality differentiation by creating two vertical sections with different heights tailored to specific functional requirements. The first vertical section with greater height addresses plasma confinement in one region, while the second vertical section with lesser height optimizes another region, allowing each part to have the precise geometry needed for its location while maintaining overall structural strength
Solution Approach 2:
The design changes the geometric parameters of the confinement ring by varying the height of vertical sections along the ring structure. This parameter variation optimizes plasma confinement characteristics at different radial positions while the overall S-shaped configuration maintains sufficient mechanical strength for operational lifetime
3Productivity
If the plasma region volume is increased to improve yield, then more plasma is available for processing, but the plasma density uniformity deteriorates and by-products accumulate
Solution Approach 1:
The asymmetric S-shaped configuration with differentiated vertical sections creates optimized plasma confinement that maintains uniform plasma density across the process region. This asymmetric design prevents plasma volume accumulation that would lead to by-product buildup while ensuring sufficient plasma availability for high-yield processing
4Reliability
If the confinement ring is designed with extended reach to cover edge ring and outer confinement ring regions, then plasma confinement improves, but the gas conductance decreases and wear becomes uneven
Solution Approach 1:
The confinement ring uses local quality variation by implementing two vertical sections with different heights at different radial positions. This allows the ring to provide enhanced confinement where needed while maintaining adequate gas conductance pathways, preventing both over-confinement that would trap by-products and under-confinement that would allow plasma escape
Data Source
AI summary
A confinement ring for use in a plasma processing chamber includes an upper horizontal section, an upper vertical section, a mid-section, a lower vertical section, a lower horizontal section and a vertical extension. The upper horizontal section extends between an inner upper radius and a first outer radius of the confinement ring. The mid-section extends between inner upper radius and a second outer radius of the confinement ring. The lower horizontal section extends between an inner lower radius and the second outer radius, and the vertical extension extends down from the lower horizontal section proximate to the inner lower radius. The upper vertical section extends between the upper horizontal section and the mid-section proximate to the inner upper radius, and the lower vertical section extends between the mid-section and the lower horizontal section proximate to the second outer radius.