Hollow cathode array and method of cleaning sheet stock therewith

• US 5,627,435 A
• Filed: 02/15/1996
• Issued: 05/06/1997
• Est. Priority Date: 07/12/1993
• Status: Expired due to Fees

• Current Assignee: BOC Group, Inc. (Messer Adolf Family)
• Original Assignee: BOC Group, Inc. (Messer Adolf Family)
• Inventors: Orban, Zoltan Jr., Krommenhoek, Steven K., Jansen, Frank, Belkind, Abraham I.
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): GAMBINO, DARUIS
• Application Number:
  US08/601,888
• Time in Patent Office: 446 Days
• Field of Search: 315/111.21, 315/111.41, 118/723 R, 118/723 MA, 118/723 E, 156/345, 156/643
• US Class Current: 315/111.21
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/32596 Hollow cathodes
• CPC Class Codes: H01J 37/3266 Magnetic control means

Abstract

An array of hollow cathodes can be made by mounting a housing connected to a source of plasma precursor gas and to a source of power in a vacuum chamber, said housing having a plurality of uniformly spaced openings in a wall thereof into which a plasma can be generated. A substrate to be treated is mounted parallel to and spaced a preselected distance from said openings. In operation, a plurality of plasma torches is created extending from the openings which can plasma etch and remove coatings on said substrate.

Claims

1. A hollow cathode array comprising

a vacuum chamber;

a housing within said chamber having a plurality of uniformly spaced openings in a wall thereof, the size of the openings and the thickness of the housing wall chosen so that a plasma is generated within the housing and emitted from the housing through said openings;

a means of supplying a plasma precursor gas to said housing; and

a means of supplying sufficient power to said housing to generate a plasma within said housing.

2. A hollow cathode array according to claim 1 wherein a substrate to be treated with said plasma discharge is mounted in said vacuum chamber parallel to and a preselected distance from said openings.

3. A hollow cathode array according to claim 2 wherein a first magnet assembly is mounted beneath said substrate.

4. A hollow cathode array according to claim 2 wherein a first magnet assembly is mounted above said substrate.

5. A hollow cathode array according to claim 3 wherein a second magnet assembly is mounted above said housing, said first and second magnet assemblies having opposite polarities.

6. A hollow cathode array according to claim 1 wherein said power source is an AC power source with a frequency from about 50 cycles per second to about 50 Megacycles per second.

7. A hollow cathode array according to claim 1 wherein said power source is an AC power source with a frequency from about 60 to about 100 kilohertz.

8. A hollow cathode array according to claim 1 wherein said power source is a DC power source.

12. A hollow cathode array according to claim 1 wherein said housing has cooling means affixed thereto.

13. A hollow cathode array according to claim 2 wherein said substrate is electrically floating.

14. A hollow cathode array according to claim 2 wherein said substrate is grounded.

9. A hollow cathode array comprising

a vacuum chamber;

a housing having a plurality of uniformly spaced openings in a wall thereof, the size of the openings and the thickness of the housing wall chosen so that a plasma is generated within said housing and emitted from said housing through said openings;

a means of supplying a plasma precursor gas to said housing;

a means of supplying sufficient power to said housing to generate a plasma within said housing, wherein said power source is an AC power source with a frequency from about 50 cycles per second to about 50 Megacycles per second; and

wherein two adjacent hollow cathodes are connected to a secondary coil of an isolation transformer.

10. A hollow cathode array according to claim 9 wherein the mid-point of said secondary coil is connected to ground through an impedance.

11. A hollow cathode array according to claim 9 wherein the mid-point of said secondary coil is shorted to ground.