Focus Ring Plasma Source for Wafer Edge Uniformity
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Solution Overview
Problem
Existing plasma processing technologies face challenges in maintaining uniformity across the edge region of semiconductor wafers due to material discontinuities, leading to non-uniform plasma processing and increased yield loss.
Innovation Solution
A plasma processing system with a focus ring containing embedded gas discharge devices generates a supplemental flow of radicals directed towards the edge region, combining with a main flow to achieve uniform radical distribution across the wafer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma processing is used without additional radical sources, then the processing is simpler, but the radical flux distribution is non-uniform across the wafer edge region
Solution Approach 1:
The radical supply system is segmented into multiple independent sources: a primary radical source providing main flow and secondary radical sources providing supplemental flow. This segmentation allows independent control of radical flux to different wafer regions, enabling uniform distribution across the edge region while maintaining overall system manageability through modular architecture
Solution Approach 2:
The patent implements local quality by providing supplemental radical flow specifically to the edge region through secondary radical sources, while the central region receives only the main radical flow. This localized enhancement addresses the specific non-uniformity problem at the wafer edge without unnecessarily complicating the entire processing system
2Manufacturing precision
If a supplemental radical source is added to improve edge uniformity, then the radical distribution becomes more uniform, but the device complexity increases
Solution Approach 1:
The patent applies partial action by introducing supplemental radical flow only where needed (the edge region) rather than uniformly across the entire wafer. This targeted approach achieves the necessary uniformity improvement with minimal additional components, avoiding excessive complexity while maintaining manufacturing precision
Solution Approach 2:
The patent introduces an intermediary radical distribution plenum that receives radicals from secondary sources and distributes them to the edge region. This intermediary component simplifies the overall system architecture by providing a centralized distribution mechanism rather than requiring multiple complex delivery systems
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 supplemental radical flow adjusts the radical flux to the edge region independently, reducing non-uniformity and yield loss by providing additional degrees of freedom in adjusting radical distribution, thus enhancing plasma processing uniformity.
Implementation Method 1
a plurality of gas discharge devices embedded in the focus ring, where each gas discharge device is configured to generate a gas discharge plasma confined within the focus ring
Implementation Method 2
a first radio frequency (RF) power supply coupled to a first RF electrode, the first RF electrode being configured to generate direct plasma over the pedestal using RF source power from the first RF power supply
Data Source
AI summary
What is described is an equipment for plasma processing including: a pedestal configured to hold a wafer; concentric with the pedestal, a focus ring including an insulator, the focus ring being positioned close to an edge region of the wafer when the wafer is held on the pedestal; and a plurality of gas discharge devices embedded in the focus ring, where each gas discharge device is configured to generate a gas discharge plasma confined within the focus ring.