Inverted Toroidal Plasma Source for Chamber Wall Cleaning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing compact inverted toroidal plasma sources face challenges in integration into semiconductor etch or deposition chambers without disrupting axial flow patterns, chamber volume, or introducing turbulence.
Innovation Solution
A novel inverted toroidal plasma source configuration with a plasma source body made of dielectric material, a ferrite core, and an electrode, which generates plasma at least partially external to the source body, allowing for reduced disruption to the vessel wall and maintaining axisymmetric flow patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compact inverted toroidal plasma source is integrated into a semiconductor chamber, then cleaning effectiveness is improved, but chamber volume is increased
Solution Approach 1:
The plasma source is nested within the chamber structure by mounting it on the chamber wall with the toroidal core positioned such that the plasma generates both inside and outside the source body. This nesting approach allows the plasma source to occupy minimal chamber volume while still delivering effective cleaning through external plasma generation.
Solution Approach 2:
The plasma source utilizes the wall-mounted configuration to generate plasma in a third dimension (external to the source body), allowing cleaning effectiveness to be improved without proportionally increasing the chamber volume. The plasma extends outward from the wall-mounted source, utilizing space that would otherwise be unused.
2Ease of operation
If a plasma source is mounted on the chamber wall, then cleaning accessibility is improved, but flow pattern disruption is increased
Solution Approach 1:
The plasma source is configured with the toroidal core and plasma generation region localized to a specific wall-mounted position, allowing cleaning to be targeted at specific areas (lower chamber, foreline) without disrupting the overall chamber flow patterns. The localized plasma generation minimizes interference with the global laminar flow structure.
Solution Approach 2:
Instead of introducing plasma from the chamber center (which would disrupt flow), the source is inverted and mounted on the wall, generating plasma outward toward the surfaces to be cleaned. This inversion allows the plasma to reach cleaning targets directly while leaving the chamber center and main flow paths undisturbed.
3Stability of the object's composition
If the plasma source body is reduced in thickness, then flow pattern disruption is reduced, but plasma stability is worsened
Solution Approach 1:
The plasma source utilizes an asymmetric configuration where the toroidal core is positioned with its major axis perpendicular to the chamber wall, creating an asymmetric plasma distribution that is stable despite the reduced thickness. The asymmetric geometry of the toroidal core (with major radius R and minor radius a) provides inherent plasma confinement and stability.
Solution Approach 2:
The toroidal core geometry with its curved surfaces provides natural plasma confinement and stability. The curved magnetic field lines generated by the toroidal core help maintain stable plasma even when the source body thickness is reduced, as the curvature provides inherent field confinement without requiring additional structural support.
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 solution enables effective integration of the plasma source into semiconductor chambers without altering the chamber volume or flow patterns, while maintaining plasma stability and efficiency for cleaning applications.
Implementation Method 1
a ferrite core within the plasma source body; wherein the plasma source body is configured to generate a plasma when the ferrite core is energized
Implementation Method 2
a plasma source body, wherein the plasma source body includes a dielectric material
Implementation Method 3
A plasma source is configured to produce plasma at least partially external to a plasma body, and/or in fluid communication with an interior of a vacuum chamber
Data Source
AI summary
A plasma source is configured to be in fluid communication with the interior of a vacuum vessel, a vacuum chamber, such as by being installed in a wall of a vacuum vessel that encloses the chamber, or in a pipe that is connected to the chamber. The plasma source may produce plasma in a line of sight of a surface to be cleaned, such as an internal surface of the vessel, which may be used for processes such as deposition or etching.