Ring Plasma Chamber Ferrite Magnetic Field Concentration
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Solution Overview
Problem
Plasma reaction chambers suffer from center-to-edge non-uniformities in neutral species distribution, leading to inconsistent plasma processing results, particularly in dielectric etch applications, due to variations in flow velocity, gas residence time, and chemistry across the substrate.
Innovation Solution
A distributed multi-zone plasma source system utilizing a ring plasma chamber with a primary winding and multiple ferrites, coupled with plasma chamber outlets that include plasma restrictions, to generate and control plasma distribution across the substrate, ensuring uniform plasma processing by concentrating magnetic fields and managing gas flow, pressure, and bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a typical parallel-plate capacitive plasma processing chamber is used, then plasma processing can be performed, but center-to-edge non-uniformities in neutral species distribution occur leading to inconsistent processing results
Solution Approach 1:
The plasma chamber is divided into multiple independently controllable zones (e.g., center zone and edge zones) with separate gas inlet ports and flow control mechanisms. This segmentation allows different gas flow rates and compositions to be applied to different regions, compensating for the natural tendency toward center-to-edge non-uniformity in parallel-plate chambers.
Solution Approach 2:
Different regions of the plasma chamber are provided with locally optimized conditions through zone-specific gas inlet ports and flow control valves. The center zone and edge zones can have different gas flow rates, pressures, or compositions tailored to achieve uniform neutral species distribution across the substrate surface.
2Productivity
If process gases are introduced across the width of the processing chamber, then plasma is formed and processing occurs, but variations in flow velocity and gas residence time cause non-uniform neutral species distribution
Solution Approach 1:
The gas delivery system is segmented into multiple zones with independent flow control. Each zone has its own inlet port and flow control valve, allowing the gas flow rate and residence time to be independently adjusted in different regions to achieve uniform plasma conditions across the chamber.
Solution Approach 2:
The gas flow rate, pressure, or composition parameters are varied locally across different zones of the plasma chamber. By changing these parameters in the center versus edge zones, the gas residence time and neutral species distribution can be equalized despite the overall gas flow across the chamber.
3Reliability
If plasma byproducts and recombination products are drawn off to the sides, then plasma processing continues, but center-to-edge non-uniformities persist due to differential removal rates
Solution Approach 1:
The plasma chamber includes multiple outlet ports distributed across different zones (center and edge) with independent pumping control. This segmentation allows differential pumping rates to be applied to different regions, maintaining uniform plasma byproduct removal and preventing accumulation that would cause non-uniformity.
Solution Approach 2:
Different zones of the plasma chamber have locally optimized outlet ports and pumping systems. The edge zones and center zone can have different pumping speeds or outlet configurations tailored to the local plasma byproduct generation rates, achieving uniform removal across the chamber.
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 system achieves improved center-to-edge uniformity in plasma processing by evenly distributing plasma byproducts and recombination products across the substrate, enhancing processing consistency and reducing non-uniformities, especially in small volume product chambers with large aspect ratios.
Implementation Method 1
a primary winding around an exterior of the ring plasma chamber
Implementation Method 2
multiple ferrites, wherein the ring plasma chamber passes through each of the ferrites
Implementation Method 3
multiple plasma chamber outlets coupling the plasma chamber to a process chamber. Each one of the plasma chamber outlets having a respective plasma restriction
Data Source
AI summary
A plasma source includes a ring plasma chamber, a primary winding around an exterior of the ring plasma chamber, multiple ferrites, wherein the ring plasma chamber passes through each of the ferrites and multiple plasma chamber outlets coupling the plasma chamber to a process chamber. Each one of the plasma chamber outlets having a respective plasma restriction. A system and method for generating a plasma are also described.