Multi-Zone Plasma Source for Uniform Etching
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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 gas flow velocity, residence time, and chemistry across the substrate.
Innovation Solution
A distributed multi-zone plasma source system utilizing multiple ring plasma chambers with primary windings and ferrites, where the primary windings are wrapped around the exterior of each ring plasma chamber, and a control system is used to manage the magnetic field and induce a secondary current in the process gas, ensuring even plasma distribution across the substrate.
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 of neutral species occur leading to inconsistent processing results
Solution Approach 1:
The plasma source is divided into multiple independent plasma generation zones (first plasma source, second plasma source, third plasma source) that can be separately controlled. Each plasma source has its own gas flow control, allowing independent optimization of plasma parameters in different regions to achieve uniform neutral species distribution across the substrate.
Solution Approach 2:
Different regions of the plasma source are provided with different gas chemistries and flow rates. The first plasma source region receives different process gases at different flow rates compared to the second and third plasma source regions, enabling local optimization of plasma characteristics to compensate for center-to-edge non-uniformities.
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, residence time, and chemistry cause non-uniform neutral species distribution
Solution Approach 1:
The single plasma source is segmented into multiple independently controllable plasma sources arranged in zones. Each zone can be optimized for specific processing requirements, allowing simultaneous maintenance of high throughput and uniform neutral species distribution by adjusting individual zone parameters.
Solution Approach 2:
Gas flow rates, pressures, and chemistries are varied across different plasma source zones to optimize plasma generation efficiency while maintaining uniform neutral species distribution. By changing parameters locally in each zone, the system achieves both high productivity and processing uniformity.
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 solution significantly reduces center-to-edge non-uniformities by evenly distributing plasma byproducts and recombination products, enhancing the consistency of plasma processing across the substrate, especially in sensitive processes like dielectric etch.
Implementation Method 1
primary windings are wrapped around an exterior of each ring plasma chamber... applying a primary current to a primary winding around an exterior of each ring plasma chamber... A magnetic field is generated in the primary windings and the magnetic field is concentrated with multiple ferrites... A secondary current is induced in the process gas in each ring plasma chamber
Implementation Method 2
multiple ferrites... The magnetic field is generated in the primary windings and the magnetic field is concentrated with multiple ferrites
Implementation Method 3
A secondary current is induced in the process gas in each ring plasma chamber... generating a plasma in the process gas in each ring plasma chamber
Data Source
AI summary
A plasma source includes multiple ring plasma chambers, multiple primary windings, multiple ferrites and a control system. Each one of the primary windings is wrapped around an exterior one of the ring plasma chambers. Each one of the plurality of the ring plasma chamber passes through a respective portion of the plurality of ferrites. The control system is coupled to each of the ring plasma chambers. A system and method for generating and using a plasma are also described.