Quartz Edge Ring Structure for Uniform Plasma Etching
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Solution Overview
Problem
Existing substrate processing systems face challenges in achieving uniform plasma processing, particularly in etching, due to the substrate edge acting as an RF antenna, leading to localized and stronger plasma striking, resulting in non-uniform etch amounts between the substrate center and edge.
Innovation Solution
The implementation of a process kit for a substrate support, comprising a conductive lower edge ring and a quartz upper edge ring, which alters the electric field near the substrate edge, shifting plasma striking from the edge to the upper edge ring and improving etch uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate edge acts as an RF antenna during plasma processing, then localized and stronger plasma striking occurs at the substrate edge, but this results in non-uniform etch amounts between the substrate center and edge
Solution Approach 1:
The patent extracts the problematic RF antenna effect from the substrate edge by introducing edge rings that intercept and redirect the RF energy and plasma striking away from the substrate edge, thereby eliminating the harmful localized plasma concentration while maintaining uniform etching across the substrate surface
Solution Approach 2:
The edge rings serve as intermediary components between the substrate and the plasma environment. These rings intercept the RF energy and plasma flux that would otherwise concentrate at the substrate edge, redistributing the energy and achieving uniform plasma processing across the entire substrate surface
2Manufacturing precision
If a process kit with edge rings is implemented to shift plasma striking from the substrate edge, then etch uniformity is improved, but the device complexity increases
Solution Approach 1:
The process kit is segmented into distinct functional components: a lower edge ring for structural support and positioning, and an upper edge ring for active plasma and RF energy interception. This segmentation allows each component to be optimized independently while working together to achieve uniform etching, making the complex function manageable and maintainable
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 enhances etch uniformity across the substrate, reduces defects and particles inside the processing chamber, and maintains a higher etch resistance, thereby improving overall substrate processing efficiency.
Implementation Method 1
alters the electric field near the substrate edge, shifting plasma striking from the 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.