Cylindrical magnetron shield structure

• US 5,464,518 A
• Filed: 09/19/1994
• Issued: 11/07/1995
• Est. Priority Date: 01/15/1993
• Status: Expired due to Fees

• Current Assignee: Applied Films Corp. (Applied Materials Incorporated)
• Original Assignee: BOC Group Pty Limited (Linde Plc)
• Inventors: Porter, John R., Sieck, Peter A.
• Primary Examiner(s): NGUYEN, NAM X
• Application Number:
  US08/308,828
• Time in Patent Office: 414 Days
• Field of Search: 204/192.12, 204/192.32, 204/192.33, 204/298.03, 204/298.11, 204/298.21, 204/298.22, 204/298.31, 204/298.32, 204/298.37
• US Class Current: 204/192.12
• CPC Class Codes: C23C 14/35 by application of a magnetic field, e.g. magnetron sputtering C23C14/3457 takes precedence
• CPC Class Codes: H01J 37/3405 Magnetron sputtering
• CPC Class Codes: H01J 37/3426 Material
• CPC Class Codes: H01J 37/3441 Dark space shields

Abstract

A rotating cylindrical sputtering target surface as part of a magnetron has cylindrical shields adjacent each end of the target that are shaped at their respective inner edges to maximize etching and to prevent condensation and subsequent arcing that undesirably occurs when certain materials, particularly dielectrics, are being sputtered. If two or more rotating targets are employed in a single magnetron system, each is similarly shielded. In an alternative form, the target is provided with a single cylindrical shield that is cut away for a significant portion of the distance around the cylinder to provide an opening through which a sputtering region of the target is accessible, while maintaining shielding of the target end regions. This alternative single shield is similarly shaped at portions of its inner edges adjacent to the opening to maximize etching and to prevent undesired condensation and subsequent arcing. The preferred shield structure is rotatable in order to allow the position of the sputtering activity to be selected.

Claims

1. A sputtering apparatus for depositing film on a substrate in a vacuum chamber, comprising:

a magnetron including therein at least one target structure with an outer cylindrically-shaped surface of sputtering material;

first and second support structures holding said target structure at opposite ends thereof such that said target structure is rotatable about its longitudinal axis;

a magnet assembly within said target structure that provides a magnetic field zone extending along a length of said sputtering material surface and extending a circumferential distance therearound;

first and second cylindrical shields, said shields carried at opposite ends of said target structure by said first and second support structures and extended axially along said sputtering material surface to substantially cover the ends of said sputtering material surface, said first shield having an inner edge closest to said second shield and said second shield having an inner edge closest to said first shield;

said inner edges being non-rectangularly shaped to conform substantially to a shape of a pattern of condensation of vaporized material on said target structure which forms when said target structure is held stationary; and

said inner edges being positioned to shield regions where condensation of vaporized material on said target structure would otherwise occur at a rate which exceeds a rate at which deposited condensate is removed from said target structure by sputtering.

3. The apparatus according to any one of claims 1 and 2, wherein each of said first and second cylindrical shields is additionally shaped with continuous portions around its circumference at each of said opposite ends that are positioned to cover said sputtering surface for a distance adjacent each of its said opposite ends and extend over adjacent portions of said first and second support structures.

4. The apparatus according to any one of claims 1 and 2, wherein said inner edges of said shields are positioned a distance from said magnetic field zone sufficient to stabilize arcing adjacent to said magnetic field zone.

5. The apparatus according to any one of claims 1 and 2, wherein said shields are connected at corresponding portions of their inner edges which are not adjacent to said magnetic field zone by a cylindrically-shaped structure extending around a portion of the circumference of said sputtering material surface that is substantially outside said magnetic field zone to form a unified shield, said unified shield having an opening at least as large as said magnetic field zone and extending around a portion of the circumference of said sputtering material surface that is substantially inside said magnetic field zone and having a length less than a distance between opposite ends of the sputtering surface of said target structure.

10. The apparatus according to any one of claims 1, 6, 9, 2 and 7, in which said inner edges adjacent to said magnetic field zone have a curved shape.

11. The apparatus according to any one of claims 1, 6, 2 and 7, in which said inner edges adjacent to said magnetic field zone have a notched shape.

2. A sputtering apparatus for depositing film on a substrate in a vacuum chamber, comprising:

a magnetron including therein at least one target structure with an outer cylindrically-shaped surface of sputtering material;

first and second support structures holding said target structure at opposite ends thereof such that said target structure is rotatable about its longitudinal axis;

a magnet assembly within said target structure that provides a magnetic field zone extending along a length of said sputtering material surface and extending a circumferential distance therearound;

first and second cylindrical shields, said shields carried at opposite ends of said target structure by said first and second support structures and extended axially along said sputtering material surface to substantially cover the ends of said sputtering material surface, said first shield having an inner edge closest to said second shield and said second shield having an inner edge closest to said first shield;

said inner edges being non-rectangularly shaped to conform substantially to a shape of a pattern of etching of sputtering material on said target structure which occurs when said target structure is held stationary; and

said inner edges being positioned to shield regions where condensation of vaporized material on said target structure would otherwise occur at a rate which exceeds a rate at which deposited condensate is removed from said target structure by sputtering.

6. A sputtering apparatus for depositing film on a substrate in a vacuum chamber, comprising:

at least one elongated target having a sputtering surface with an outside cylindrical shape of a given diameter and a given length between first and second ends thereof;

first and second support structures respectively supporting said first and second sputtering surface ends in a manner that allows said target to rotate about a central longitudinal axis thereof;

means positioned within said target for providing a magnetic field zone extending along a length of said sputtering surface and a circumferential distance therearound;

electrically controlled driving means coupled to said target structure for rotating said sputtering surface through said magnetic field zone;

first and second cylindrical shields separated by a distance of less than substantially one-quarter inch from said sputtering surface for minimizing condensation of vaporized material at said first and second sputtering surface ends, said shields carried at opposite ends of said target by said first and second support structures and extended axially along said sputtering surface to substantially cover the ends of said sputtering surface, said shields having continuous portions extending around the circumference of said first and second ends positioned to cover said sputtering surface for a distance adjacent each of its said first and second ends and extend over adjacent portions of said first and second support structures, said first shield having an inner edge closest to said second shield and said second shield having an inner edge closest to said first shield;

said inner edges being non-rectangularly shaped to conform substantially to a shape of a pattern of condensation of vaporized material on said target structure which forms when said target structure is held stationary; and

said inner edges being positioned to shield regions where condensation of vaporized material on said target structure would otherwise occur at a rate which exceeds a rate at which deposited condensate is removed from said target structure by sputtering.

8. The apparatus according to any one of claims 6 and 7, wherein said inner edges of said shields are positioned a distance from said magnetic field zone sufficient to stabilize arcing adjacent to said magnetic field zone.

9. The apparatus according to any one of claims 6 and 7, wherein said shields are connected at corresponding portions of said inner edges which are not adjacent to the magnetic field zone by a cylindrically-shaped structure extending around a portion of the circumference of said sputtering surface that is substantially outside said magnetic field zone to form a unified shield, said unified shield having an opening at least as large as said magnetic field zone and extending around the portion of the circumference of said sputtering surface that is substantially inside said magnetic field zone and having a length less than a distance between said first and second ends of said sputtering surface.

7. A sputtering apparatus for depositing film on a substrate in a vacuum chamber, comprising:

at least one elongated target having a sputtering surface with an outside cylindrical shape of a given diameter and a given length between first and second ends thereof;

first and second support structures respectively supporting said first and second sputtering surface ends in a manner that allows said target to rotate about a central longitudinal axis thereof;

means positioned within said target for providing a magnetic field zone extending along a length of said sputtering surface and a circumferential distance therearound;

electrically controlled driving means coupled to said target structure for rotating said sputtering surface through said magnetic field zone;

first and second cylindrical shields separated by a distance of less than substantially one-quarter inch from said sputtering surface for minimizing condensation of vaporized material at said first and second sputtering surface ends, said shields carried at opposite ends of said target by said first and second support structures and extended axially along said sputtering surface to substantially cover the ends of said sputtering surface, said shields having continuous portions extending around the circumference of said first and second ends positioned to cover said sputtering surface for a distance adjacent each of its said first and second ends and to extend over adjacent portions of said first and second support structures, said first shield having an inner edge closest to said second shield and said second shield having an inner edge closest to said first shield;

said inner edges being non-rectangularly shaped to conform substantially to a shape of a pattern of etching of sputtering material on said target structure which occurs when said target structure is held stationary; and

said inner edges being positioned to shield regions where condensation of vaporized material on said target structure would otherwise occur at a rate which exceeds a rate at with deposited condensate is removed from said target structure by sputtering.

12. A method of forming cylindrical end shields for use in a sputtering apparatus for depositing film on a substrate in a vacuum chamber comprised of a rotating cylindrical magnetron including therein at least one rotatable target structure, having an outer cylindrically-shaped surface of sputtering material and held at opposite ends thereof by first and second support structures, a magnet assembly within said target structure that provides a magnetic field zone, and first and second cylindrical end shields carried at opposite ends of said target structure by said support structures, said first shield having an inner edge closest to said second shield and said second shield having an inner edge closest to said first shield, comprising the steps of:

(a) operating said rotating cylindrical magnetron such that said magnetic field zone is provided and said target structure is immobile;

(b) determining positions on said immobilized target structure where condensation of material vaporized during said operation has occurred; and

(c) shaping said shields at said inner edges, non-rectangularly, to conform substantially to a pattern of said positions determined in step (b).

13. The method of claim 12, additionally comprising the step of optimizing the distance between said shields and said magnetic field zone by placing said shields on said opposite ends of a cylindrical sputtering structure, operating said rotating cylindrical magnetron, recording arcing activity using recording means, and adjusting said distance to minimize said arcing activity.

14. The method of claim 12, additionally comprising the step of optimizing the distance between said shields and said magnetic field zone by placing said shields on said opposite ends of a cylindrical sputtering structure, operating said rotating cylindrical magnetron, recording voltage within the vacuum chamber of the sputtering apparatus using recording means, and adjusting said distance to minimize variations in voltage adjacent to said magnetic field zone.

15. The method of claim 12, additionally comprising the step of connecting said end shields at portions of said inner edges which are not adjacent to said magnetic field zone by a cylindrically-shaped structure extending around the portion of the circumference of a cylindrical sputtering structure that is substantially outside said magnetic field zone to form a unified shield, said unified shield having an opening at least as large as said magnetic field zone and extending around the portion of the circumference of said cylindrical sputtering structure that is substantially inside said magnetic field zone and having a length less than a distance between opposite ends of said cylindrical sputtering structure.

16. The method of claim 12, additionally comprising the steps of:

(a) optimizing the distance between said shields and said magnetic field zone by placing said shaped shields on said opposite ends of a cylindrical sputtering structure, operating said rotating cylindrical magnetron such that said magnetic field zone is provided, recording arcing activity using recording means, and adjusting said distance to minimize said arcing activity; and

(b) connecting said end shields at portions of said inner edges which are not adjacent to said magnetic field zone by a cylindrically-shaped structure extending around the portion of the circumference of said cylindrical sputtering structure that is substantially outside said magnetic field zone to form a unified shield, said unified shield having an opening at least as large as said magnetic field zone and extending around the portion of the circumference of said cylindrical sputtering structure that is substantially inside said magnetic field zone and having a length less than a distance between opposite ends of said cylindrical sputtering structure.

17. The method of claim 12, additionally comprising the steps of:

(a) optimizing the distance between said shields and said magnetic field zone by placing said shaped shields on said opposite ends of a cylindrical sputtering structure, operating said rotating cylindrical magnetron such that said magnetic field zone is provided, recording voltage within the vacuum chamber of the sputtering apparatus using recording means, and adjusting said distance to minimize variations in voltage adjacent to said magnetic field zone; and

(b) connecting said end shields at portions of said inner edges which are not adjacent to said magnetic field zone by a cylindrically-shaped structure extending around the portion of the circumference of said cylindrical sputtering structure that is substantially outside said magnetic field zone to form a unified shield, said unified shield having an opening at least as large as said magnetic field zone and extending around the portion of the circumference of said cylindrical sputtering structure that is substantially inside said magnetic field zone and having a length less than a distance between opposite ends of said cylindrical sputtering structure.

18. The method according to claim 12, in which the shaping step includes shaping said shields at said inner edges such that said inner edges have a curved shape.

19. The method according to claim 12, in which the shaping step includes shaping said shields at said inner edges such that said inner edges have a notched shape.

20. A method of sputter etching a cylindrical sputtering structure using a sputtering apparatus for depositing film on a substrate in a vacuum chamber comprised of a rotating cylindrical magnetron including therein at least one rotatable target structure, having an outer cylindrically-shaped surface of sputtering material and held at opposite ends thereof by first and second support structures, and a magnet assembly within said target structure that provides a magnetic field zone, comprising the steps of:

(a) operating said rotating cylindrical magnetron such that said magnetic field is provided and said target structure is held stationary;

(b) determining a shape of a pattern of condensation of vaporized material on said target structure which forms when said rotating cylindrical magnetron is operated according to step (a); and

(c) blocking regions at opposite ends of said target structure where condensation of vaporized material on said target structure would otherwise occur at a rate which exceeds a rate at which deposited condensate is removed from said target structure by sputtering using blocking means, said blocking means being non-rectangularly shaped to conform substantially to the shape of the pattern of condensation determined according to step (b) and positioned to shield said regions.

21. The method of claim 20, wherein said blocking means extends around the portion of the circumference of said cylindrical sputtering structure that is substantially outside said magnetic field zone.

22. A sputtering apparatus for depositing film on a substrate in a vacuum chamber, comprising:

a magnetron including therein at least one target structure with an outer cylindrically-shaped surface of sputtering material;

first and second support structures holding said target structure at opposite ends thereof such that said target structure is rotatable about its longitudinal axis;

a magnet assembly within said target structure that provides a magnetic field zone extending along a length of said sputtering material surface and extending a circumferential distance therearound;

first and second cylindrical shields, said shields carried at opposite ends of said target structure by said first and second support structures and extended axially along said sputtering material surface to substantially cover the ends of said sputtering material surface, said first shield having an inner edge closest to said second shield and said second shield having an inner edge closest to said first shield; and

said inner edges being non-rectangularly shaped to conform substantially to a pattern of deposition of vaporized material on said target structure adjacent to the ends thereof which is determinable when said magnetron is operated without rotating said target structure.

23. The apparatus according to claim 22, wherein the pattern is curved.

24. The apparatus according to claim 22, wherein the inner edges of the shields are positioned along a longitudinal axis of said target structure to cover regions where vaporized material would otherwise be deposited at a rate that exceeds a rate at which such deposited material is removed by sputtering.

25. In a magnetron including a vacuum chamber and therein, at least one elongated cylindrical sputtering surface rotatable about an axis thereof and a magnetic structure carried non-rotatably therewithin and extending along a length thereof, a method of depositing a material on a substrate positioned within the chamber by sputtering from the sputtering surface, comprising:

(a) defining a pattern of deposition of vaporized material on the sputtering surface adjacent to ends thereof which is determinable when the magnetron is operated without rotating the sputtering surface;

(b) shielding regions of the sputtering surface where vaporized material would otherwise be deposited, with shields having non-rectangular inner edges substantially conforming to the defined pattern; and

(c) operating the magnetron with the sputtering surface rotating and the shields held non-rotatably.

26. The method according to claim 25, wherein the defined pattern is curved.

27. The method according to claim 25, wherein step (b) includes positioning the edges of the shields along a longitudinal axis of the sputtering surface to cover regions where vaporized material would otherwise be deposited at a rate that exceeds a rate at which deposited material is removed by sputtering.

28. A method of forming cylindrical end shields for use in a sputtering apparatus for depositing film on a substrate in a vacuum chamber comprised of a rotating cylindrical magnetron including therein at least one rotatable target structure, having an outer cylindrically-shaped surface of sputtering material and held at opposite ends thereof by first and second support structures, a magnet assembly within said target structure that provides a magnetic field zone, and first and second cylindrical end shields carried at opposite ends of said target structure by said support structures, said first shield having an inner edge closest to said second shield and said second shield having an inner edge closest to said first shield, comprising the steps of:

(a) defining a pattern of deposition of vaporized material on the target structure adjacent to the ends thereof which would occur if the magnetron were operated without rotating the target structure;

(b) shaping the inner edges of the shields, non-rectangularly, to conform substantially to the defined pattern.

29. The method of claim 28, wherein the defined pattern is curved.

30. The method of claim 28, further comprising the step of optimizing the distance between the inner edges of the shields along a longitudinal axis of the sputtering surface, thereby shielding regions where vaporized material would otherwise be deposited at a rate that exceeds a rate at which deposited material is removed by sputtering.