System and method for controlling thin film defects

• US 20030150712A1
• Filed: 02/13/2003
• Published: 08/14/2003
• Est. Priority Date: 02/13/2002
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Reiter, Jeffrey Shane, Cai, Zhiwei, Barlow, Stephen Eric
• Granted Patent: US 6,835,290 B2
• Time in Patent Office: Days
• US Class Current: 204/192.12
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: C23C 14/3421 using heated targets
• CPC Class Codes: C23C 14/352 using more than one target C23C14/56 takes precedence
• CPC Class Codes: H01J 37/3405 Magnetron sputtering

Abstract

A system and method for reducing and controlling the number of defects due to carbon inclusions on magnetic media is disclosed. A diamond like carbon protective layer is deposited on magnetic media using a rotary cathode target assembly. The target and cathode are cylindrical in shape and are mounted on holder that allows the target and cathode to rotate while holding a magnet fixed. The target surface is periodically swept in through a plasma which sputters off the surface of the target. This prevents the build up of redeposited material on the target and consequently keeps the target surface cleaner. The reduction of redeposited material on the target surface reduces the number of unwanted particulates which are ejected from the surface, manifesting themselves as disk defects.

Claims

1. A method of depositing a thin film, the method comprising the steps of:

subjecting a portion of an outside surface of a target to a plasma;

rotating said target to subject substantially all of the outside surface of said target to said plasma; and

transporting a substrate in front of said target to deposit a thin film on said substrate.

2. The method of claim 1 wherein said step of subjecting a portion of an outside surface of a target to a plasma further includes the step of confining said plasma.

3. The method of claim 1 wherein said step of subjecting a portion of an outside surface of a target to a plasma further includes the step of sputtering said target.

4. The method of claim 1 wherein said step of rotating said target includes rotating said target at a rotation rate of about 1 revolution per minute to about 100 revolutions per minute.

5. The method of claim 1 wherein said step of rotating said target includes rotating said target at a rotation rate of about 10 revolutions per minute.

6. The method of claim 1 wherein said step of transporting a substrate in front of said target further includes passing said substrates through a sputtering pattern.

7. The method of claim 1 wherein said step of transporting a substrate in front of said target further includes passing said substrates through a sputtering pattern at a constant speed.

8. A method of depositing a thin film, the method comprising the steps of:

rotating a target relative to a plasma to sputter said target and clean said target; and

transporting a substrate in front of said target to deposit a thin film on said substrate.

9. A system for reducing defects on a substrate during sputter deposition comprising:

a target rotatable about an axis and having an outside surface;

a power supply to supply a voltage to said target, said voltage sufficient to generate a plasma;

a magnet operatively positioned relative to said target and producing a magnetic field sufficient to penetrate said target to confine said plasma near a portion of the outside surface of said target upon application of said voltage to said target, said portion of the outside surface of said target exposed to said plasma;

a rotatable holder for rotating said target along said axis and relative to said magnet, and upon complete rotation of said target, a substantial portion of said outside surface of said target is exposed to said plasma; and

a transport for moving a substrate in front of said target.

10. The transport of claim 9 further having a pallet for holding a plurality of substrates.

11. The transport of claim 9 further having an adjustable speed.

12. The system of claim 9 wherein said target includes carbon.

13. The system of claim 9 wherein said magnet is a permanent magnet.

14. The system of claim 9 further comprising a coolant for cooling said target and said magnet.

15. The system of claim 9 further comprising a second target, a second magnet, and a second rotatable holder, said second target operatively positioned to permit movement of said substrate between said target and said second target.

16. The system of claim 9 further comprising a chamber substantially enclosing said target, said magnet, said rotatable holder, and said transport, said chamber capable of maintaining a vacuum.

17. The system of claim 16 further including a cathode located inside said chamber, said cathode electrically connected to said target and said power supply.

18. The system of claim 17 wherein said cathode is substantially enclosed by said target.

19. The chamber of claim 16 further comprising a vacuum feed-through for coupling said transport to an external motor.

20. A system for reducing defects on a substrate during sputter deposition, comprising:

a target with an outside surface;

means for confining a plasma to expose a portion of the outside surface of said target to said plasma;

means for rotating said target to expose substantially all of the outside surface of said target to said plasma; and

means for moving a substrate in front of said target.