Substrate Support Edge Ring Layout for Uniform Plasma Processing
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Solution Overview
Problem
Substrate processing systems face non-uniformities due to variations in substrate size and manufacturing tolerances, leading to issues like temperature and electric field non-uniformities, which result in uneven etch depths and increased erosion of ceramic layers exposed to plasma, necessitating frequent maintenance and replacement.
Innovation Solution
A substrate support design featuring a ceramic layer with an increased outer radius relative to the edge ring, allowing the ceramic layer to extend below the edge ring, and incorporating a replaceable insert in an annular groove to mitigate non-uniformities and reduce erosion, thereby improving process uniformity and reducing maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ceramic layer outer radius is increased to improve process uniformity, then temperature and electric field uniformity improve, but the ceramic layer is more exposed to plasma and suffers increased erosion
Solution Approach 1:
The ceramic layer is segmented into two functional zones: an extended outer perimeter portion that provides process uniformity, and a standard inner portion that is protected by the edge ring. This segmentation allows the system to benefit from the extended ceramic radius for uniformity while the edge ring protects the replaceable insert from erosion.
Solution Approach 2:
A replaceable insert is introduced as a sacrificial component that can be easily replaced when eroded. This insert is positioned in the annular groove at the extended outer perimeter of the ceramic layer, allowing the system to maintain process uniformity while replacing only the worn insert rather than the entire ceramic layer.
2Manufacturing precision
If the ceramic layer extends below the edge ring to improve edge performance, then process uniformity improves, but maintenance frequency increases due to erosion
Solution Approach 1:
The ceramic layer structure is segmented with the edge ring providing protection for the inner portion while the extendable outer perimeter (with replaceable insert) is exposed to plasma. This segmentation allows the protected inner portion to maintain structural integrity while the outer portion can be replaced when eroded.
Solution Approach 2:
The replaceable insert is designed to be discarded when eroded and replaced with a new insert. This approach allows rapid recovery of process uniformity without replacing the entire ceramic layer or edge ring assembly, minimizing downtime and maintenance frequency.
3Reliability
If a replaceable insert is added to the annular groove, then erosion resistance improves through easy replacement, but device complexity increases
Solution Approach 1:
The ceramic layer is segmented with an annular groove creating a distinct replaceable insert region. This segmentation isolates the complex replaceable insert mechanism to only the necessary outer perimeter area, rather than complicating the entire ceramic structure.
Solution Approach 2:
The annular groove structure serves multiple functions: it provides a retention feature for the insert, creates a replacement interface, and defines the boundary between protected and exposed ceramic regions. This multi-functionality reduces the need for additional separate components.
Data Source
AI summary
A substrate support for supporting a substrate in a substrate processing system includes a baseplate and a ceramic layer arranged above the baseplate. An outer perimeter of the ceramic layer is surrounded by an edge ring. An outer radius of the ceramic layer is greater than an inner radius of the edge ring such that an outer edge of the ceramic layer extends below the edge ring.