Plasma Reactor Electrode Assembly for Uniform Processing
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Solution Overview
Problem
Conventional plasma reactors face challenges in achieving uniform plasma distribution and repeatability, especially when the workpiece moves through the plasma region, leading to non-uniform processing and potential charging damage due to localized power deposition and inadequate RF grounding.
Innovation Solution
The processing tool incorporates a unique intra-chamber electrode assembly with coplanar filaments that extend laterally across the plasma chamber, allowing for relative motion between the workpiece and the plasma region, and utilizes a recursive RF feed structure to ensure uniform plasma generation and efficient power coupling, while maintaining a low impedance RF ground path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plasma reactors use stationary workpiece support, then the structure is simple, but plasma uniformity and repeatability deteriorate when workpiece moves through plasma region
Solution Approach 1:
The electrode assembly is segmented into multiple coplanar filaments arranged in a specific pattern, allowing each filament to contribute to uniform plasma distribution across the workpiece surface while maintaining overall system reliability
Solution Approach 2:
The system enables relative motion between the workpiece support and plasma region through rotation or linear movement, transforming the stationary configuration into a dynamic one that maintains plasma uniformity during workpiece processing
2Power
If conventional RF power supply is used, then power coupling is simple, but plasma power coupling efficiency deteriorates
Solution Approach 1:
The RF power supply is segmented into multiple independent RF power sources, each connected to individual coplanar filaments, enabling precise power distribution and improved plasma power coupling efficiency across different regions of the plasma chamber
Solution Approach 2:
The coplanar filaments are arranged and connected to create equipotential surfaces that optimize RF power distribution, ensuring uniform plasma generation and efficient power coupling across the entire workpiece surface
3Reliability
If conventional grounding structure is used, then the structure is simple, but plasma uniformity deteriorates due to inadequate RF grounding
Solution Approach 1:
The grounding structure is segmented into multiple grounding points distributed across the chamber, with each coplanar filament having its own RF ground connection, ensuring adequate RF grounding throughout the plasma region for uniform plasma generation
Solution Approach 2:
Multiple grounding points are strategically positioned to create equipotential regions that eliminate RF voltage gradients, ensuring uniform plasma distribution and preventing charging damage across the workpiece surface
4Productivity
If workpiece moves through plasma region, then throughput increases, but within-wafer uniformity deteriorates due to localized power deposition
Solution Approach 1:
The plasma source is segmented into multiple coplanar filaments that can be independently controlled, allowing compensation for localized power deposition variations as the workpiece moves through the plasma region, maintaining within-wafer uniformity while enabling continuous processing
Solution Approach 2:
Different regions of the coplanar filament array provide locally optimized plasma characteristics, with each filament zone tailored to compensate for specific motion-induced non-uniformities, ensuring consistent processing quality across the entire workpiece surface during movement
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 plasma uniformity and repeatability, reduces metal contamination and particle generation, and enhances plasma power coupling efficiency, resulting in better within-wafer uniformity and increased throughput.
Implementation Method 1
a first RF power source to supply a first RF power to the conductors of the electrode assembly to form a plasma
Implementation Method 2
One of the two metal electrodes are driven by a radio frequency (RF) power supply at a fixed frequency while the other electrode is connected to an RF ground, generating an RF electric field between the two electrodes. The generated electric field ionizes the gas atoms, releasing electrons.
Implementation Method 3
an actuator to generate relative motion between the chamber body and the workpiece support such that the opening moves laterally across the workpiece
Data Source
AI summary
A processing tool for a plasma process includes a chamber body that has an interior space that provides a plasma chamber and that has a ceiling and an opening on a side opposite the ceiling, a workpiece support to hold a workpiece such that at least a portion of a front surface of the workpiece faces the opening, an actuator to generate relative motion between the chamber body and the workpiece support such that the opening moves laterally across the workpiece, a gas distributor to deliver a processing gas to the plasma chamber, an electrode assembly comprising a plurality of coplanar filaments extending laterally through the plasma chamber between the workpiece support and the ceiling, each of the plurality of filaments including a conductor, and a first RF power source to supply a first RF power to the conductors of the electrode assembly to form a plasma.