ENHANCED PLASMA MODE AND SYSTEM FOR PLASMA IMMERSION ION IMPLANTATION

• US 20010017109A1
• Filed: 11/29/1999
• Published: 08/30/2001
• Est. Priority Date: 12/01/1998
• Status: Abandoned Application

• Current Assignee: Silicon Genesis
• Original Assignee: Silicon Genesis
• Inventors: LIU, WEI, CHAN, CHUNG, BRYAN, MICHAEL A., ROTH, IAN S.
• Application Number:
  US09/451,204
• Publication Number:
  US 20010017109A1
• Time in Patent Office: Days
• US Class Current: 118/723I
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: C23C 16/507 using external electrodes, e.g. in tunnel type reactors
• CPC Class Codes: H01J 37/32412 Plasma immersion ion implantation
• CPC Class Codes: H01J 37/3266 Magnetic control means

Abstract

A novel plasma treatment system (200). The plasma treatment system has a chamber (14), where a vacuum is maintained. The system also has a susceptor disposed within an interior region in the chamber. The susceptor (i.e., electrostatic chuck) is adapted to secure a work piece thereon. The system has an rf source (40) disposed overlying the susceptor. The rf source provides an inductive discharge to form a plasma from a gas within the chamber. Magnetic sources (207), (209) are selectively applied to the plasma discharge. In a specific embodiment, a first magnetic source (207) is disposed surrounding the susceptor in the chamber. The first magnetic source provides focused magnetic field lines toward the susceptor. A second magnetic source (209) is disposed surrounding the susceptor, where the second magnetic source provides focussed magnetic field lines toward the susceptor. The combination of the rf source and the magnetic sources form a plasma discharge that is shaped as a “cusp” which focuses the plasma discharge.

Claims

1. A plasma immersion ion implantation (PIII) system, said system comprising:

a chamber;

a susceptor disposed within an interior region in said chamber, said susceptor being adapted to secure a work piece thereon;

an rf source disposed overlying said susceptor in said chamber, said rf source providing an inductive discharge to form a plasma from a gas within said chamber;

a first electro-magnetic source disposed surrounding said susceptor in said chamber, said first magnetic source providing focused magnetic field lines toward said susceptor; and

a second-electro magnetic source disposed surrounding said susceptor in said chamber, said second magnetic source providing focussed magnetic field lines toward said susceptor.

2. The system of

claim 1

wherein said rf source is a single coil disposed overlying an upper surface of said chamber.

3. The system of

claim 1

wherein said rf source comprises a plurality of coils, each of said coils being disposed overlying an upper surface of said chamber.

4. The system of

claim 2

further comprising a tuning circuit coupled to said rf source.

5. The system of

claim 1

wherein said plasma comprises a first cusp region toward said rf plasma source and a second cusp near a chamber side.

6. The system of

claim 1

wherein said plasma comprises a first cusp region toward said susceptor and a second cusp near a chamber side.

7. The system of

claim 1

wherein said first electro-magnetic source and said second electro-magnetic source prevent a substantial portion of said plasma from occupying a region directly adjacent to a wall of said chamber.

8. The system of

claim 1

wherein said first electro-magnetic source is coupled to a direct current power supply.

9. The system of

claim 1

wherein said second electro-magnetic source is coupled to a direct current power supply.

10. The system of

claim 1

wherein said first electro-magnetic source is coupled to a direct current power supply, said direct current power supply providing current that flows in a first direction.

11. The system of

claim 10

wherein said second electro-magnetic source is coupled to a direct current power supply, said direct current power supply providing current that flows in a second direction, said second direction being opposite of said first direction.

12. The system of

claim 1

further comprising a source of hydrogen gas, said source being coupled to said chamber.

13. The system of

claim 1

wherein said plasma is a hydrogen bearing plasma.

14. The system of

claim 1

wherein said plasma is substantially a hydrogen bearing plasma of H₁⁺ particles.

15. The system of

claim 1

further comprising a power source coupled between said susceptor and said plasma.

16. The system of

claim 15

wherein said power source capable of accelerating particles from said plasma into and through a surface of said work piece to a selected depth underlying said surface of said work piece.

17. The system of

claim 1

wherein said chamber is a vacuum chamber that is maintained at a pressure of about 0.1 millitorr to about 1.0 milltorr.

18. A plasma immersion ion implantation (PIII) source, said source comprising:

a vacuum chamber;

a susceptor disposed within an interior region in said chamber, said susceptor being adapted to secure a work piece thereon;

an rf source disposed overlying said susceptor in said chamber, said rf source providing an inductive discharge to form a plasma from a gas within said chamber; and

a first electro-magnetic source disposed surrounding an upper portion of said chamber, said first magnetic source providing a first cusp region of said plasma toward said rf source.

19. The source of

claim 18

further comprising a second electro-magnetic source disposed surrounding a lower portion of said chamber, said second electro-magnetic source providing a second cusp region of said plasma toward said susceptor.

20. The source of

claim 18

wherein said first electro-magnetic source is coupled to a direct current power source.

21. The source of

claim 18

wherein said rf source is a single coil disposed overlying an upper surface of said chamber.

22. The source of

claim 21

wherein said coil is configured to maximize an rf power delivered to a center of a plasma within said chamber.

23. The source of

claim 21

, wherein said rf source, said first magnetic source and said second magnetic source are configured to couple helicon waves to a plasma within said chamber.

24. A method for producing a substantially pure monatomic ion species in a plasma in a chamber for plasma immersion ion implantation (PIII), the method comprising:

providing an inductive discharge to form a plasma from a gas within said chamber;

providing a first set of focused magnetic field lines within the chamber that form a first cusp proximate a first end of the chamber; and

providing a second set of focused magnetic field lines within the chamber that form a second cusp proximate a second end of the chamber, wherein the first and second sets of magnetic field lines interact to form a third cusp intermediate the first and second cusps.

25. The method of

claim 24

wherein further comprising:

coupling rf energy to the gas within the chamber.

26. The method of

claim 25

wherein the rf energy excites a helicon electron cyclotron resonance mode of the plasma.

27. The method of

claim 26

wherein the rf energy excites a Trivelpiece-Gould mode of the plasma.

28. The method of

claim 24

wherein the plasma is used for a plasma ion implantation process.

29. The method of

claim 24

wherein the plasma is used for a separation by plasma implantation technology process.

30. The method of

claim 24

wherein the plasma is substantially a monatomic hydrogen ion plasma.