Plasma Reactor Electrode Array for Uniform Ionization
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Solution Overview
Problem
Plasma reactors face challenges in producing uniform plasma over large workpieces, maintaining repeatability, reducing metal contamination, and controlling ion energy, especially when the workpiece is moving and lacks an adequate RF ground path.
Innovation Solution
A plasma reactor design featuring a chamber with a dielectric top and bottom plate, a plurality of conductors arranged in a parallel coplanar array, and an RF power source that applies RF signals with a 180° phase difference to improve plasma uniformity and power coupling efficiency, while minimizing metal contamination and particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a basic CCP source with two metal electrodes is used, then plasma is generated through RF electric field ionization, but metal contamination occurs and plasma uniformity over large workpieces deteriorates
Solution Approach 1:
The invention extracts and removes the problematic metal electrodes from the plasma generation system. Instead of using traditional metal electrodes that cause contamination, the patent employs a metal-free electrode structure consisting of a dielectric layer with embedded conductive patterns, thereby eliminating metal contamination while maintaining plasma generation capability
Solution Approach 2:
The invention introduces a dielectric layer as an intermediary between the RF power source and the plasma. This dielectric layer with embedded conductive patterns serves as a mediator that enables RF power coupling to generate plasma without direct contact between metal electrodes and plasma, thus preventing metal contamination
2Stability of the object's composition
If traditional plasma sources are used, then plasma is generated, but plasma uniformity over large workpiece areas deteriorates
Solution Approach 1:
The invention segments the electrode structure into multiple conductive patterns embedded in the dielectric layer. These segmented conductive patterns can be independently controlled to generate localized plasma regions, enabling uniform plasma distribution across large workpiece areas by coordinating multiple segments
Solution Approach 2:
The invention implements local quality by allowing different regions of the dielectric layer with embedded conductive patterns to have different electrical properties and plasma generation characteristics. This enables tailored plasma uniformity across different areas of the workpiece, accommodating variations in workpiece size and shape
3Adaptability or versatility
If the workpiece is moved without an adequate RF ground path, then processing flexibility is improved, but plasma repeatability deteriorates
Solution Approach 1:
The dielectric layer with embedded conductive patterns acts as an intermediary that provides a stable RF reference potential without requiring direct metal electrode contact. This mediator enables workpiece movement while maintaining consistent plasma generation conditions, ensuring plasma repeatability despite workpiece position changes
Solution Approach 2:
The invention replaces the traditional mechanical RF grounding system with a field-based approach using the dielectric layer and embedded conductive patterns. This substitution eliminates the need for precise mechanical RF ground paths, allowing workpiece movement while maintaining plasma consistency through electromagnetic field stabilization
4Object-affected harmful factors
If metal electrodes are used for plasma generation, then plasma is produced, but particle generation and contamination increase
Solution Approach 1:
The invention extracts and eliminates metal electrodes from the system, replacing them with a metal-free dielectric structure with embedded conductive patterns. This removal of metal components directly reduces particle generation and contamination while maintaining effective plasma power coupling through the alternative electrode structure
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 design enhances plasma uniformity and repeatability, reduces metal contamination, and improves plasma power coupling efficiency, maintaining consistent plasma properties over varying operating conditions even with a moving workpiece.
Implementation Method 1
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 2
a dielectric bottom plate between the electrode assembly and the workpiece support, the dielectric bottom plate providing an RF window between the electrode assembly and the plasma chamber
Data Source
AI summary
A plasma reactor includes a chamber body having an interior space that provides a plasma chamber, a gas distributor to deliver a processing gas to the plasma chamber, a workpiece support to hold a workpiece, an electrode assembly comprising a plurality of conductors spaced apart from and extending laterally across the workpiece support in a parallel coplanar array, a first RF power source to supply a first RF power to the electrode assembly, and a dielectric bottom plate between the electrode assembly and the workpiece support, the dielectric bottom plate providing an RF window between the electrode assembly and the plasma chamber.