Compensation of spacing between magnetron and sputter target

• US 20050133361A1
• Filed: 09/16/2004
• Published: 06/23/2005
• Est. Priority Date: 12/12/2003
• Status: Abandoned Application

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lubben, Daniel C., Ding, Peijun, Yoshidome, Goichi, Rengarajan, Suraj, Sundarrajan, Arvind, Hong, Ilyoung Richard, Miller, Michael Andrew, Yang, Hsien-Lung
• Application Number:
  US10/942,358
• Publication Number:
  US 20050133361A1
• Time in Patent Office: Days
• US Class Current: 204/192.120
• CPC Class Codes: C23C 14/3407 Cathode assembly for sputtering apparatus, e.g. Target
• CPC Class Codes: C23C 14/35 by application of a magnetic field, e.g. magnetron sputtering C23C14/3457 takes precedence
• CPC Class Codes: C23C 14/54 Controlling or regulating the coating process
• CPC Class Codes: H01J 37/3408 Planar magnetron sputtering
• CPC Class Codes: H01J 37/3455 Movable magnets

Abstract

A lift mechanism for and a corresponding use of a magnetron in a plasma sputter reactor. A magnetron rotating about the target axis is controllably lifted away from the back of the target to compensate for sputter erosion, thereby maintaining a constant magnetic field and resultant plasma density at the sputtered surface, which is particularly important for stable operation with a small magnetron, for example, one executing circular or planetary motion about the target axis. The lift mechanism can include a lead screw axially fixed to the magnetron support shaft and a lead nut engaged therewith to raise the magnetron as the lead nut is turned. Alternatively, the support shaft is axially fixed to a vertically moving slider. The amount of lift may be controlled according a recipe based on accumulated power applied to the target or by monitoring electrical characteristics of the target.

Claims

1. In a magnetron sputter reactor including a chamber sealable to a sputtering target, a support in said reactor for holding a substrate to be processed, and a magnetron placeable on a backside of said target opposite said support, a magnetron control system comprising:

a lift mechanism affixed to a support of said magnetron capable of varying a distance of said magnetron from said backside of said target; and

a controller for controlling a degree of said varying said distance during processing of a sequence of substrates.

2. The lift mechanism of claim 1, including a motor driving said lift mechanism in response to said controller.

3. A sputter reactor, comprising:

a target affixed to vacuum chamber;

a pedestal within said chamber for support a substrate in opposition to said target;

a magnetron positioned on a back side of said target;

a power supply selectively applying power to said target to excite a plasma within said chamber to thereby sputter material from a front side of said target onto said substrate;

a mechanism for varying a spacing between said magnetron and said target; and

a controller controlling said mechanism to adjust said spacing during a predetermined sequence of depositing said material onto a plurality of said substrates.

4. The reactor of claim 3, wherein said controller adjusts said spacing to compensate for an erosion of said front side of said target by said plasma.

5. A method of sputtering onto a substrate support on a support in a sputtering reactor chamber including a target fixed to said chamber and a magnetron disposed on a back of said target opposite said support, comprising:

plural first steps of exciting a plasma in said chamber and depositing material of said target onto sequential ones of a plurality of substrates; and

plural second steps of lifting said magnetron away from said backside of said target performed during or after different ones of said first steps.

6. The method of claim 5, further comprising rotating said magnetron about a central axis of said target.

7. The method of claim 5, wherein said rotating step causes said magnetron to execute planetary motion about said central axis.

8. The method of any claim 5, wherein said second steps lift said magnetron to compensate for an erosion depth of said target after said target enters service.

9. A magnetron sputtering method, comprising adjusting a magnetic field, which is assisting generation of a plasma in sputtering a target, in compensation for erosion of a front of said target by particles from said plasma.

10. The method of claim 9, wherein said adjusting comprises moving a magnetron away from a back of said target.

11. The method of claim 9, wherein said adjusting reduces variations in said magnetic field at said front of said target caused by said erosion.

12. The method of claim 9, wherein said adjusting reduces variations in said plasma at said front of said target caused by said erosion.

13. The method of claim 9, wherein a degree of said adjusting is determined according to a recipe for said sputtering.

14. A method for use with a plasma sputter reactor chamber mounting a target facing an interior of the chamber and with a magnetron positioned on the backside of said target exteriorly of the chamber, comprising the steps of:

exciting a plasma in said chamber so as to deposit material of said target onto sequential ones of a plurality of substrates;

lifting said magnetron away from the backside during or after said exciting of said plasma or deposition of material; and

a controller controlling a degree of said lifting at an intermediate time of processing of said plurality of substrates.

15. The method of claim 14, wherein said controller controls said degree of said lifting according to an amount of erosion of a front side of said target during processing of said plurality of substrates.

16. The method of claim 14, wherein there is no substantial effective movement of said magnetron towards said target during a sequence of depositions of said material onto different substrates.

17. The method of claim 16, in which said lifting of said magnetron is performed during or after any one or more of said exciting of said plasma or said depositing of material.

18. The method of claim 16, in which said lifting is at performed plural different times.

19. The method of claims 14, further comprising rotating said magnetron about a central axis of said target to execute circular movement about said central axis.

20. The method of claim 14, further comprising rotating said magnetron to execute planetary motion about said central axis.

21. A hollow cathode sputter reactor, comprising:

a vacuum chamber arranged about a central axis;

a support within said chamber for holding a substrate to be processed;

a sputter target sealable to said chamber and having a right cylindrical vault arranged about said central axis in opposition to said support formed by a generally disk-shaped roof and a generally tubular sidewall;

a magnet assembly disposed adjacent a back surface of either said roof or said sidewall; and

a lift mechanism supporting said magnet assembly and controllably varying a distance between said magnet assembly and said back surface.

22. The reactor of claim 21, wherein said lift mechanism includes an actuator controllably moving a support member of said magnet assembly.