Quartz Upper Edge Ring for Plasma Uniformity
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Solution Overview
Problem
Substrate processing systems face challenges in achieving uniform plasma processing due to the substrate edge acting as an RF antenna, leading to localized and stronger plasma striking, resulting in center-to-edge non-uniformity during etch processes.
Innovation Solution
The implementation of a process kit comprising a conductive lower edge ring and an upper edge ring made of quartz, where the lower edge ring raises the RF conductive surface, altering the electric field to redirect plasma striking from the substrate edge to the upper edge ring, thereby enhancing processing uniformity and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the substrate edge acts as an RF antenna during plasma processing, then the plasma striking becomes localized and stronger at the substrate edge, but this results in center-to-edge non-uniformity in etch processes
Solution Approach 1:
The patent introduces an upper edge ring made of quartz as an intermediary component between the substrate and the lower edge ring. This upper edge ring serves as a mediator that intercepts and redirects the plasma striking away from the substrate edge, preventing the substrate edge from acting as an RF antenna and thereby resolving the non-uniformity issue while maintaining controlled plasma intensity
Solution Approach 2:
The patent employs a composite structure consisting of two different materials: a conductive lower edge ring (made of aluminum or aluminum alloy) and an insulating upper edge ring (made of quartz). This composite design allows the lower ring to provide RF conductivity for plasma control while the upper ring acts as a dielectric barrier to redirect plasma, achieving both uniform etching and controlled plasma distribution
2Manufacturing precision
If a process kit with upper and lower edge rings is implemented to redirect plasma striking, then etch uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent divides the edge ring into two separate functional segments: a lower edge ring for RF conductivity and structural support, and an upper edge ring for plasma redirection. This segmentation allows each component to be optimized for its specific function and facilitates easier manufacturing, installation, and maintenance while achieving the overall goal of improved etch uniformity
3Manufacturing precision
If the lower edge ring raises the RF conductive surface to alter the electric field, then plasma striking is redirected from the substrate edge, but the quantity of components increases
Solution Approach 1:
The patent combines multiple functions into the two-edge-ring system: the lower edge ring provides both structural support and RF conductivity, while the upper edge ring provides both plasma redirection and additional structural stability. This merging of functions into integrated components achieves the desired plasma distribution uniformity without requiring a excessive number of separate parts
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
This configuration improves etch uniformity across the substrate, reducing defects and particles within the chamber while maintaining a higher etch resistance and processing efficiency.
Implementation Method 1
One technique useful for controlling aspects of such substrate processing is use of radio frequency (RF) energy to control a plasma proximate the substrate
Implementation Method 2
the lower edge ring raises the RF conductive surface, altering the electric field to redirect plasma striking
Implementation Method 3
use of radio frequency (RF) energy to control a plasma proximate the substrate
Implementation Method 4
an upper edge ring made of quartz... configured to interface with the lower edge ring... redirect plasma striking from the substrate edge to the upper edge ring
Data Source
AI summary
Methods and apparatus for processing substrates are provided herein. In some embodiments, a process kit for a substrate support includes: an upper edge ring made of quartz and having an upper surface and a lower surface, wherein the upper surface is substantially planar and the lower surface includes a stepped lower surface to define a radially outermost portion and a radially innermost portion of the upper edge ring.