Spring-loaded mount for a rotatable sputtering cathode

• US 5,620,577 A
• Filed: 01/24/1996
• Issued: 04/15/1997
• Est. Priority Date: 12/30/1993
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Viratec Thin Films, Inc. (Apogee Enterprises Incorporated)
• Inventors: Taylor, Clifford L.
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/590,811
• Time in Patent Office: 447 Days
• Field of Search: 204/298.11, 204/298.22
• US Class Current: 204/298.22
• CPC Class Codes: C23C 14/3407 Cathode assembly for sputtering apparatus, e.g. Target
• CPC Class Codes: H01J 37/3405 Magnetron sputtering
• CPC Class Codes: H01J 37/3435 Target holders (includes backing plates and endblocks)
• CPC Class Codes: H01J 37/3441 Dark space shields

Abstract

A rotatable magnetron cathode has one end adapted to be attached to a drive shaft and a free end supported by a yoke suspended from spring-loaded supporting devices attached to a sputtering chamber wall. A dark space shield is attached to the cathode where the cathode connects to the drive shaft of its motor so as to rotate with the cathode. Another dark space shield is attached at the free end of the cathode with an insulator bearing in between such that the cathode can rotate without causing the shield at its front to also rotate. An insulator pad is placed between the yoke and a metal cover piece attached to the shield at the front so as to keep the frontal dark space shield in an electrically floating condition.

Claims

1. A rotating magnetron cathode apparatus, comprising:

a cylindrical tubular structure with a first end which is rotatably supported and a second end which is distal from said first end;

a frontal dark space shield at said second end of said cylindrical tubular structure;

mounting means for rotatably mounting said frontal dark space shield onto said second end of said cylindrical tubular structure without electrical conduction therebetween and such that said frontal dark shield remains stationary while said cylindrical tubular structure rotates; and

said frontal dark space shield including a cylindrical tubular sleeve having an outer diameter less than a diameter of said cylindrical tubular structure.

2. The rotating magnetron cathode apparatus of claim 1 further comprising a rotating dark space shield mounted onto said cylindrical tubular structure around said first end so as to rotate together with said cylindrical tubular structure, there being no electrical conduction between said cylindrical tubular structure and said rotating dark space shield.

3. The rotating magnetron cathode apparatus of claim 1 wherein said frontal dark space shield comprises a circular disk part with an external surface, an internal surface opposite said external surface, and an externally protruding tubular part protruding from said external surface of said circular disk part, said mounting means including:

a front flange having a base affixed to said cylindrical tubular structure at said second end and a cylindrical part protruding from said base; and

a tubular insulator bearing inserted coaxially between said externally protruding tubular part of said frontal dark space shield and said cylindrical part of said front flange.

4. The rotating magnetron cathode of apparatus claim 3 wherein said base of said front flange has a frustoconical part.

5. The rotating magnetron cathode apparatus of claim 3 wherein said base of said front flange and said internal surface of said circular disk part are separated by a distance less than a dark space length.

6. The rotating magnetron cathode apparatus of claim 3 wherein said sleeve protrudes from peripheries of said internal surface of said circular disk part and wherein said outer diameter of said sleeve is greater than the diameter of said base of said flange so said sleeve covers said second end of said tubular structure.

7. The rotating magnetron cathode apparatus of claim 3 wherein said mounting means further include a cover piece attached to said externally protruding tubular part of said frontal dark space shield.

8. The rotating magnetron cathode apparatus of claim 3 wherein said cylindrical part of said front flange has a screw-accepting hole axially formed therethrough, said mounting means further including a washer which is attached to said tubular insulator bearing and a screw which is passed through said insulator bearing and is inserted into said screw-accepting hole.

9. A rotating magnetron apparatus comprising:

an evacuable chamber;

a drive shaft;

a cathode disposed inside said evacuable chamber having a first end detachably attached to said drive shaft and a second end distal from said first end;

a frontal dark space shield at said second end of said cathode;

spring loaded supporting means attached to a wall of said chamber for vertically supporting said second end of said cathode while allowing radial displacement of said second end; and

mounting means for rotatably mounting said frontal dark space shield onto said cathode without electrical conduction therebetween.

10. The rotating magnetron apparatus of claim 9 wherein said spring loaded supporting means include:

a pair of spring loaded supporting devices attached to said chamber wall;

a yoke which is suspended from said pair of supporting devices; and

an insulating pad placed between said yoke and said frontal dark space shield.

11. The rotating magnetron apparatus of claim 10 wherein said yoke includes insulating members, said yoke being suspended from said pair of supporting devices through said insulating members.

12. The rotating magnetron apparatus of claim 11 wherein said frontal dark space shield comprises a circular disk part with an external surface, an internal surface opposite said external surface, and an externally protruding tubular part protruding from said external surface of said circular disk part, said mounting means including:

a front flange having a base affixed to said cylindrical tubular structure at said second end and a cylindrical part protruding from said base; and

a tubular insulator bearing inserted coaxially between said externally protruding tubular part of said frontal dark space shield and said cylindrical part of said front flange.

13. The rotating magnetron apparatus of claim 12 wherein said mounting means further include a cover piece attached to said externally protruding tubular part of said frontal dark space shield, said yoke supporting said cylindrical cathode by contacting said cover piece with said insulating pad therebetween.

14. The rotating magnetron apparatus of claim 10 wherein said frontal dark space shield comprises a circular disk part with an external surface, an internal surface opposite said external surface, and an externally protruding tubular part protruding from said external surface of said circular disk part, said mounting means including:

a front flange having a base affixed to said cylindrical tubular structure at said second end and a cylindrical part protruding from said base;

a tubular insulator bearing inserted coaxially between said externally protruding tubular part of said frontal dark space shield and said cylindrical part of said front flange.

15. The rotating magnetron apparatus of claim 14 further including a cover piece attached to said externally protruding tubular part of said frontal dark space shield, said yoke supporting said cylindrical cathode by contacting said cover piece with said insulating pad therebetween.

16. The rotating magnetron apparatus of claim 9 wherein said frontal dark space shield comprises a circular disk part with an external surface, an internal surface opposite said external surface, and an externally protruding tubular part protruding from said external surface of said circular disk part, said mounting means including:

a front flange having a base affixed to said cylindrical tubular structure at said second end and a cylindrical part protruding from said base; and

a tubular insulator bearing inserted coaxially between said externally protruding tubular part of said frontal dark space shield and said cylindrical part of said front flange.

17. The rotating magnetron apparatus of claim 12 wherein said mounting means further include a cover piece attached to said externally protruding tubular part of said frontal dark space shield, said spring loaded supporting means supporting said cylindrical cathode by contacting said cover piece.

18. A rotating magnetron apparatus comprising:

an evacuable chamber;

a drive shaft;

a cathode disposed inside said evacuable chamber having a first end detachably attached to said drive shaft and a second end distal from said first end; and

spring loaded supporting means attached to a wall of said chamber for vertically supporting said second end of said cathode while allowing radial displacement of said second end.

19. The rotating magnetron apparatus of claim 18 wherein said spring loaded supporting means include:

a pair of spring loaded supporting devices attached to said chamber wall;

a yoke which is suspended from said pair of supporting devices; and

an insulating pad placed between said yoke and said second end of said cathode.

20. The rotating magnetron apparatus of claim 19 wherein each said spring-loaded supporting device comprises:

a housing having at least one cavity having an opening at a top of said housing;

in each said cavity, means passing through said opening for connection to a chamber wall; and

in each said cavity, a spring connecting said housing and said means for connection to said chamber wall.

21. A rotating magnetron cathode apparatus, comprising:

a cylindrical tubular structure with a first end that is rotatably supported and a second end that is distal from the first end;

a frontal dark space shield including a circular disk part with an external surface and an externally protruding tubular part protruding from said external surface;

a front flange having a base affixed to said cylindrical tubular structure at said second end and a cylindrical part protruding from said base; and

a tubular insulator bearing disposed coaxially between said externally protruding tubular part of said frontal dark space shield and said cylindrical part of said front flange so that said frontal dark space shield is rotatably mounted at said second end.