Edge Ring Assembly for Plasma Etching Uniformity
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Solution Overview
Problem
Plasma etching in semiconductor manufacturing often results in undesirable byproduct deposition on the substrate's lateral edges and underside, which can negatively impact process yield and chamber component wear.
Innovation Solution
An edge ring assembly comprising a dielectric coupling ring and a conductive edge ring is used in plasma etching chambers, where the conductive edge ring is supported on the dielectric coupling ring, reducing byproduct deposition and enhancing plasma uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plasma etching is performed without an edge ring assembly, then the etching process can proceed, but byproduct deposition occurs on the substrate's lateral edges and underside, reducing process yield
Solution Approach 1:
The harmful byproduct deposition on substrate edges is extracted and redirected onto the sacrificial edge ring instead. The edge ring assembly captures the deposited byproducts that would otherwise contaminate the substrate, effectively removing the harmful effect from the substrate processing area.
Solution Approach 2:
The edge ring assembly acts as an intermediary component between the plasma environment and the substrate. It provides a sacrificial surface that intercepts byproduct deposition, protecting the substrate from contamination while maintaining the plasma etching process.
2Duration of action of stationary object
If no edge ring is used, then the chamber structure is simpler, but the substrate support suffers from erosion by plasma, reducing chamber longevity
Solution Approach 1:
The edge ring is designed as a sacrificial, consumable component that protects more critical chamber parts. By using a replaceable edge ring that can be easily replaced, the system extends the life of the substrate support and other expensive chamber components, improving overall chamber longevity despite the added structural complexity.
Solution Approach 2:
The edge ring assembly is installed in advance to protect the substrate support from plasma erosion before damage occurs. This preliminary protective measure prevents erosion of critical components, extending chamber life and reducing maintenance frequency.
3Manufacturing precision
If a conductive edge ring is used, then plasma uniformity is improved, but the device complexity increases due to the combination of dielectric and conductive components
Solution Approach 1:
The edge ring assembly uses different materials with different electrical properties in different regions. The dielectric coupling ring provides electrical isolation, while the conductive edge ring portion provides plasma uniformity. This local differentiation of material properties allows the system to achieve both electrical isolation and plasma uniformity without requiring a completely complex redesign.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The edge ring assembly decreases byproduct deposition, improves plasma etching uniformity, and reduces wear on chamber components, thereby enhancing process yield and chamber longevity.
Implementation Method 1
the dielectric coupling ring can be functional to reduce RF coupling and undesirable arcing between the conductive edge ring and the substrate support
Implementation Method 2
Plasma etching, in turn, can be used to transfer the pattern formed in the photoresist layer to one or more layers formed on the substrate that underlie the photoresist layer
Implementation Method 3
Edge rings can be disposed around the substrate support (i.e., around the substrate) for confining plasma to the space above the substrate and/or to protect the substrate support from erosion by the plasma
Data Source
AI summary
An edge ring assembly used in a plasma etching chamber includes a dielectric coupling ring and a conductive edge ring. In one embodiment, the dielectric coupling ring has an annular projection extending axially upward from its inner periphery. The dielectric coupling ring is adapted to surround a substrate support in a plasma etching chamber. The conductive edge ring is adapted to surround the annular projection of the dielectric coupling ring. A substrate supported on the substrate support overhangs the substrate support and overlies the annular projection of the dielectric coupling ring and a portion of the conductive edge ring. In another embodiment, the dielectric coupling ring has a rectangular cross section. The dielectric coupling ring and the conductive edge ring are adapted to surround a substrate support in a plasma etching chamber. A substrate supported on the substrate support overhangs the substrate support and overlies a portion of the conductive edge ring.