Wide-Coverage Edge Ring Structure for Plasma Shielding
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Solution Overview
Problem
Existing substrate processing systems face issues with edge rings that do not provide sufficient protection to underlying components from ion bombardment during etching, leading to frequent replacement and reduced mean time between cleaning (MTBC) due to exposure to plasma.
Innovation Solution
A wide-coverage edge ring design that extends beyond the outer diameter of the bottom ring and interfaces with the chamber liner, creating a serpentine path to shield underlying components, minimizing direct exposure to plasma and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the edge ring outer diameter is made small to pass through transfer ports, then the edge ring can be transferred through the system, but the coverage area is insufficient and underlying components are exposed to plasma
Solution Approach 1:
The edge ring design extends in the vertical dimension by incorporating a projection that extends above the chamber liner upper end. This vertical extension creates an overlapping shielding arrangement that blocks plasma paths without requiring an increase in the horizontal outer diameter, thus maintaining transferability while enhancing protection coverage.
Solution Approach 2:
The edge ring is divided into functional segments: a main body portion for plasma shaping, a projection portion for extended shielding above the liner, and a lower surface step for interface with the bottom ring. This segmentation allows each portion to perform its specific function optimally while maintaining overall compactness for transfer through ports.
2Area of stationary object
If the edge ring outer diameter is increased to provide wider coverage, then protection of underlying components is improved, but the edge ring cannot pass through transfer ports
Solution Approach 1:
Instead of increasing the horizontal outer diameter to expand coverage, the design utilizes the vertical dimension by extending a projection above the chamber liner. This allows the edge ring to maintain a compact horizontal footprint for easy transfer while providing extended vertical coverage for enhanced protection.
Solution Approach 2:
The projection is strategically positioned at specific angular locations (e.g., 0, 90, 180, 270 degrees) rather than providing uniform 360-degree extension. This localized quality approach provides protection where most needed while minimizing the overall outer diameter, ensuring transferability is maintained.
3Ease of operation
If the edge ring provides minimal coverage, then transfer through ports is easy, but ion bombardment quickly erodes underlying components requiring frequent replacement
Solution Approach 1:
The projection extending above the chamber liner acts as a protective shield that intercepts plasma and ions before they can reach the chamber liner upper end and bottom ring. This beforehand protection prevents erosion of underlying components, extending their operational life and increasing MTBC while maintaining easy transferability.
Solution Approach 2:
The projection serves as an intermediary protective element positioned between the plasma environment and the chamber liner/bottom ring. It absorbs the harmful ion bombardment, protecting the more valuable underlying components from erosion and extending their service life.
4Reliability
If the projection extends above the chamber liner, then shielding coverage is enhanced, but device complexity increases
Solution Approach 1:
Rather than creating a complex structure with full 360-degree projection, the design uses localized projections at specific angular positions (e.g., four projections at 0, 90, 180, 270 degrees). This provides effective shielding where plasma exposure is most severe while maintaining manufacturing simplicity and reducing overall device complexity.
Solution Approach 2:
The projection extends partially above the chamber liner rather than providing complete coverage. This partial action is sufficient to block the primary plasma paths and provide the necessary shielding effectiveness without requiring a complex full-coverage structure, thus balancing protection with simplicity.
Data Source
AI summary
A wide-coverage edge ring configured to be arranged above a bottom ring in a substrate processing chamber includes an upper surface, a lower surface that includes a lower surface step that extends downward from the lower surface and is configured to be received within and interface with a pocket defined at least partially by an upper surface of the bottom ring and an inner surface of a chamber liner, an inner diameter, a ledge defined in the inner diameter of the edge ring, and an outer diameter. The outer diameter of the edge ring includes a projection that extends radially outward from the edge ring and defines an inward step in the outer diameter, the projection and the inward step are configured to interface with an upper end of the chamber liner, and the projection is configured to extend at least partially over the upper end of the chamber liner.