Plasma Cleaning Confinement for Substrate Uniformity
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Solution Overview
Problem
Existing substrate cleaning methods, such as plasma etching, face challenges in achieving uniform cleaning, especially in embossments and salient parts, like cutting edges of tool bodies, due to inadequate plasma density distribution.
Innovation Solution
A method involving a vacuum chamber with a plasma discharge between an electron source cathode and an anode arrangement, where the anode electrode is confined within a structure operating on a different electric potential, concentrating ion density near the substrate, which is positioned on a negative potential, to enhance cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used for substrate cleaning, then the cleaning process can be performed, but uniform cleaning is not achieved in embossments and salient parts due to inadequate plasma density distribution
Solution Approach 1:
The patent applies local quality by creating a confinement structure with different electric potentials to generate localized high plasma density regions adjacent to the substrate surface. This confined plasma discharge concentrates reactive species exactly where needed - in embossments and salient parts - rather than relying on uniform plasma distribution throughout the chamber.
Solution Approach 2:
The patent changes the electric potential parameter by applying different potentials to the confinement structure versus the substrate holder. This parameter change creates strong electric fields that concentrate ions and electrons in specific regions, transforming the plasma density distribution from uniform to highly localized, thereby improving cleaning uniformity in complex surface features.
2Manufacturing precision
If plasma density is increased to improve cleaning uniformity, then cleaning effectiveness improves, but risk of arcing and processing damage increases
Solution Approach 1:
By confining high plasma density to specific regions adjacent to the substrate rather than throughout the entire chamber, the patent achieves high cleaning effectiveness locally while maintaining lower overall plasma density. This localized approach prevents the widespread arcing and processing damage that would result from uniformly high plasma density.
Solution Approach 2:
The confinement structure acts as an intermediary element between the plasma source and the substrate. It mediates the plasma discharge by confining it to specific regions, thereby achieving high cleaning effectiveness while preventing the harmful arcing that would occur with uncontrolled high-density plasma exposure.
3Quantity of substance
If conventional plasma discharge configuration is used, then the process is simple, but plasma density adjacent to substrate surface is insufficient for effective cleaning
Solution Approach 1:
The patent segments the plasma discharge configuration by introducing a separate confinement structure distinct from the substrate holder. This segmentation allows independent control of plasma density regions, enabling high plasma density adjacent to the substrate surface without requiring complete redesign of the entire discharge system.
Solution Approach 2:
The confinement structure serves as an intermediary component that enhances plasma density at the substrate surface without requiring fundamental changes to the plasma source. This intermediary element achieves the desired effect with minimal added complexity compared to conventional direct plasma discharge configurations.
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 approach increases plasma density adjacent to the substrate, ensuring improved uniform cleaning within complex surface features, leading to enhanced etching rates and prevention of processing damage from arcing.
Implementation Method 1
establishing in a vacuum chamber having a reaction space and containing a gas to be ionized at least one plasma discharge between at least one electron source cathode and at least one anode arrangement
Implementation Method 2
containing a gas to be ionized
Implementation Method 3
providing the anode electrode within the confinement and operating the confinement on an electric potential which is different from an electric potential applied to the anode electrode, thereby concentrating increased ion density in the confinement and adjacent the opening
Implementation Method 4
The cleaning process which is used for manufacturing such cleaned substrates is, generically spoken, plasma etching, being non-reactive or being reactive
Data Source
AI summary
Plasma etch-cleaning of substrates is performed by means of a plasma discharge arrangement comprising an electron source cathode (5) and an anode arrangement (7). The anode arrangement (7) comprises on one hand an anode electrode (9) and on the other hand and electrically isolated therefrom a confinement (11). The confinement (11) has an opening (13) directed towards an area (S) of a substrate (21) to be cleaned. The electron source cathode (5) and the anode electrode (9) are electrically supplied by a supply circuit with a supply source (19). The circuit is operated electrically floating.