Dual hexagonal shaped plasma source

• US 8,454,810 B2
• Filed: 07/14/2006
• Issued: 06/04/2013
• Est. Priority Date: 07/14/2006
• Status: Active Grant

• Current Assignee: 4D-S Pty, Ltd.
• Original Assignee: 4D-S Pty, Ltd.
• Inventors: Nagashima, Makoto
• Primary Examiner(s): Hendricks, Keith
• Assistant Examiner(s): BERMAN, JASON
• Application Number:
  US11/486,471
• Publication Number:
  US 20080011600A1
• Time in Patent Office: 2,517 Days
• Field of Search: 204/298.09, 204/298.18, 204/198.26, 204/298.26
• US Class Current: 204/298.26
• CPC Class Codes: C23C 14/3407 Cathode assembly for sputtering apparatus, e.g. Target
• CPC Class Codes: C23C 14/352 using more than one target C23C14/56 takes precedence
• CPC Class Codes: H01J 37/3405 Magnetron sputtering
• CPC Class Codes: H01J 37/342 Hollow targets
• CPC Class Codes: H01J 37/3452 Magnet distribution

Abstract

A plasma source includes a hexagonal hollow cathode, the cathode including six targets and six magnets to generate and maintain a high density plasma; and an anode located beneath the cathode. A second hexagonal hollow cathode can be positioned concentric to the hexagonal hollow cathode.

Claims

1. A hollow cathode magnetron, comprising:

a first hexagonal hollow cathode, the cathode including six targets arranged in a hexagonal shape and one or more magnets associated with each of the six targets to generate and maintain a high density plasma;

a second hexagonal hollow cathode including six targets arranged in a hexagonal shape located concentric to the first hexagonal hollow cathode and one or more magnets associated with each of the six targets; and

an anode located beneath the cathode,

wherein,

each target having one or more magnets with a single radially oriented polarity with respect to the first and second concentric hexagonal hollow cathodes;

magnets associated with adjacent targets having opposite magnetic polarity;

the magnetic field lines of the first and second hexagonal hollow cathode couple to each other;

magnetic field lines are used to generate plasma from the injected inert gas; and

plasma ions impact the six targets of each hexagonal hollow cathode, thereby enhancing the erosion profile of the six targets.

2. The hollow cathode magnetron of claim 1, comprising a plurality of magnets below the targets and positioned so as to form a tapered magnetic convergent lens between the cathode and a wafer.

3. The hollow cathode magnetron of claim 1, wherein the magnets comprise a first, second, third, fourth, fifth and sixth electromagnetic coils.

4. The hollow cathode magnetron of claim 1, wherein the plurality of magnets are vertically spaced between the target and a wafer.

5. The hollow cathode magnetron of claim 1, wherein the magnets generate magnetic fields to gradually confine ionized target atoms towards a wafer.

6. A sputtering system comprising the hollow cathode magnetron of claim 1, including:

an air-tight chamber in which an inert gas is admittable and exhaustible;

magnets respectively disposed adjacent to said target plates such that magnet poles of different polarities face each other across said plasma region thereby to establish a magnetic field of said plasma region between said target plates;

a substrate holder disposed adjacent to said plasma region, said substrate holder adapted to hold a substrate on which an alloyed thin film is to be deposited; and

a back-bias power supply coupled to the substrate holder.

7. The system of claim 6, wherein the back-bias power supply is a DC or an AC electric power source.

8. The system of claim 6, comprising first and second target power supplies to provide DC or AC electric power sources.

9. The system of claim 6, wherein the plasma source maintains the plasma within the cathode.

10. The system of claim 6, further comprising a chuck heater mounted above the wafer.

11. A method of magnetron sputtering, comprising:

generating a high density plasma within a cathode of a hexagonal shaped hollow cathode magnetron wherein the hexagonal shaped hollow cathode magnetron comprises a first hexagonal hollow cathode and a second hexagonal hollow cathode concentric to the first hexagonal hollow cathode and wherein each hexagonal hollow cathode comprises six targets and each target having one or more magnets with a single radially oriented polarity with respect to the first and second concentric hexagonal hollow cathodes;

magnets associated with adjacent targets having opposite magnetic polarity; and

the magnetic field lines of the first and second hexagonal hollow cathode couple to each other;

using the plasma to sputter atoms from a target in the hexagonal shaped hollow cathode magnetron; and

forming a tapered magnetic convergent lens between the hexagonal shaped hollow cathode magnetron and a substrate using a plurality of magnets below the hexagonal shaped hollow cathode magnetron, wherein magnetic field lines are aligned in a z-direction and are used to generate plasma from the injected inert gas, wherein plasma ions impact the six targets, thereby enhancing the erosion profile of the six targets.

12. The method of claim 11, comprising the act of maintaining the plasma within the cathode.

13. The method of claim 11, wherein the magnets modulate magnetic fields to gradually confine ionized target atoms.

14. The method of claim 11, comprising:

providing at least one target and a substrate having a film-forming surface portion and a back portion;

creating a magnetic field so that the film-forming surface portion is placed in the magnetic field with the magnetic field induced normal to the substrate surface portion back-biasing the back portion of the substrate; and

sputtering material onto the film-forming surface portion.

15. The method of claim 11, comprising supporting a chuck from underneath rather than side-way.

16. The method as in claim 11, comprising providing a plurality of sources to deposit materials onto the substrate.