Plasma source and surface treatment method

Patent metadata

Field	Value
Publication number	US-11352696-B2
Application number	US-201515321847-A
Country	US
Kind code	B2
Filing date	Jun 25, 2015
Priority date	Jun 25, 2014
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A plasma source has an outer surface, interrupted by an aperture for delivering an atmospheric plasma from the outer surface. A transport mechanism transports a substrate in parallel with the outer surface, closely to the outer surface, so that gas from the atmospheric plasma may form a gas bearing between the outer surface the and the substrate. A first electrode of the plasma source has a first and second surface extending from an edge of the first electrode that runs along the aperture. The first surface defines the outer surface on a first side of the aperture. The distance between the first and second surface increasing with distance from the edge. A second electrode covered at least partly by a dielectric layer is provided with the dielectric layer facing the second surface of the first electrode, substantially in parallel with the second surface of the first electrode, leaving a plasma initiation space on said first side of the aperture, between the surface of the dielectric layer and the second surface of the first electrode. A gas inlet feeds into the plasma initiation space to provide gas flow from the gas inlet to the aperture through the plasma initiation space. Atmospheric plasma initiated in the plasma initiation space flows to the aperture, from which it leaves to react with the surface of the substrate.

First claim

The invention claimed is:

1. A plasma source, comprising:
an outer surface, interrupted by an aperture for delivering an atmospheric plasma from the outer surface;
a first electrode having a first and second surface extending from an edge of the first electrode that runs along the aperture, the first surface defining the outer surface on a first side of the aperture, the distance between the first and second surface increasing with distance from the edge;
a second electrode at a fixed position relative to the first electrode and a dielectric layer covering at least part of the second electrode, at least part of a surface of the dielectric layer facing the second surface of the first electrode, substantially in parallel with the second surface of the first electrode, leaving a plasma initiation space on said first side of the aperture, between the surface of the dielectric layer and the second surface of the first electrode;
a gas inlet in communication with the plasma initiation space to provide gas flow from the gas inlet to the aperture through the plasma initiation space, wherein:
the first electrode comprises a first and second portion on opposite sides of the aperture respectively, the first and second surface being surfaces of the first portion,
the second portion having a third and fourth surface extending from a second side of the aperture opposite the first side, the third surface defining the outer surface on the second side of the aperture, the distance between the third and fourth surface increasing with distance from an edge of the second portion along the second side of the aperture,
a further part of the dielectric layer facing the fourth surface, substantially in parallel with the fourth surface, leaving a further plasma initiation space on said second side of the aperture, between the surface of the dielectric layer and the fourth surface;
a further gas inlet in communication with the further plasma initiation space to provide gas flow from the further gas inlet to the aperture through the further plasma initiation space;

first ridges between the second surface of the first electrode and the surface of the dielectric layer, running through the plasma initiation space leaving openings between the first ridges for the gas flow towards the aperture; and
second ridges between the fourth surface and the surface of the dielectric layer, running through the further plasma initiation space leaving openings between the second ridges for the gas flow towards the aperture, positions of projections of the first ridges on to the first side of the aperture lying between positions of projections of the second ridges on to the second side of the aperture;
wherein substantially no space remains for gas flow between the first electrode and the dielectric layer at contact surfaces where the first and second ridges are formed.

2. A plasma source according to claim 1 , further comprising a transport mechanism configured to transport a substrate and the plasma source relative to each other parallel to the outer surface, with a surface to be processed of the substrate in parallel with at least a part of the outer surface that contains the aperture, wherein the transport mechanism is configured to position a surface of the substrate that faces the outer surface of the plasma source at a distance of at most half a millimeter from each other.

3. A plasma source according to claim 1 , wherein the first ridges or the second ridges define openings between pairs of adjacent ridges formed on a same surface, each of the openings allowing a respective part of the gas flow to flow from the gas inlet towards the edge of the first electrode, the respective parts flowing in parallel with each other through the plasma initiation space.

4. A plasma source according to claim 1 , wherein a width of the aperture is smaller than five times a distance from the dielectric layer at the aperture to a virtual extension of the outer surface through the aperture.

5. A plasma source according to claim 1 , wherein the second electrode has at least a surface part that extends in parallel to the second surface of the first electrode, the plasma initiation space lying between said surface part of the second electrode and the second surface of the first electrode, said at least part of a surface of the dielectric layer lying on said surface part of the second electrode between the second electrode and the plasma initiation space.

6. A plasma source according to claim 1 , wherein the first ridges run in parallel in a direction from the gas inlet towards the first side of the aperture and the second ridges run in parallel in a direction from the further gas inlet towards the second side of the aperture, the positions of projections of the first ridges on to the first side of the aperture lying midway between the positions of projections of the second ridges on to the first side of the aperture.

7. A plasma source according to claim 1 , wherein the first ridges and the second ridges end short of the edges of the first and second portion at the first and second side of the aperture.

8. A plasma source according to claim 1 , wherein the aperture has a width between the first and second side of the aperture of between one and five millimeter.

9. A plasma source according to claim 1 , further comprising a transport mechanism configured to transport a substrate and the plasma source relative to each other parallel to the outer surface, with a surface to be processed of the substrate in parallel with at least a part of the outer surface that contains the aperture, wherein the transport mechanism is configured to transport the substrate and the plasma source relative to each other using the gas flow as a gas bearing to keep the substrate and the outer surface apart adjacent the aperture once the gas flow has emerged from the aperture.

10. A plasma source according to claim 1 , further comprising a transport mechanism configured to transport a substrate and the plasma source relative to each other parallel to the outer surface, with a surface to be processed of the substrate in parallel with at least a part of the outer surface that contains the aperture, wherein the transport mechanism comprises one of a conveyor belt for transporting the substrate, a table and a motor configured to drive the table, and a roll to roll mechanism.

11. A plasma source according to claim 1 , wherein each of the first ridges has an endpoint proximate the aperture and running through the plasma initiation space, and each of the second ridges has an endpoint proximate the aperture and running through the further plasma initiation space, wherein a distance from the aperture to positions along a longest direction of the ridge increases with distance from the endpoint to the positions.

12. The plasma source according to claim 1 , wherein the first ridges and/or the second ridges have a width that diminishes with decreasing distance to the aperture.

13. The plasma source according to claim 1 , wherein the first and second ridges are formed of dielectric material, and the first and second ridges are configured with a height that forms contact surfaces between the first ridges and the second surface and between the second ridges and the fourth surface of the first electrode, such that substantially no space remains for gas to flow through the contact surfaces of the first and second dielectric and/or conductive ridges.

14. The plasma source according to claim 1 , wherein the first and second ridges are formed of electrically conductive material, and the first and second ridges are configured with a height that forms cont

Assignees

• TNO
• Nederlandse Organisatie Voor Toegepast—Natuurwetenschappelijk Onderzoek Tno

Inventors

• Creyghton Yves Lodewijk Maria
• Poodt Paulus Willibrordus George
• Simor Marcel
• Roozeboom Freddy

Classifications

• H05H1/2441

  characterised by the physical-chemical properties of the dielectric, e.g. porous dielectric · CPC title

• H05H1/2439

  Surface discharges, e.g. air flow control · CPC title

• H01J37/32348 Primary

  Dielectric barrier discharge · CPC title

• C23C16/45514 Primary

  Mixing in close vicinity to the substrate · CPC title

• H01J37/32715

  Workpiece holder · CPC title