Enhanced plasma mode and system for plasma immersion ion implantation

• US 6,300,227 B1
• Filed: 12/01/1998
• Issued: 10/09/2001
• Est. Priority Date: 12/01/1998
• Status: Expired due to Term

• Current Assignee: Silicon Genesis
• Original Assignee: Silicon Genesis
• Inventors: Bryan, Michael A., Roth, Ian S., Liu, Wei
• Primary Examiner(s): DANG, THI D
• Application Number:
  US09/203,025
• Time in Patent Office: 1,043 Days
• Field of Search: 156/345, 118/723.I, 118/723.IR, 204/298.37, 216/68, 438/732, 438/798, 438/514, 438/515, 438/513
• US Class Current: 438/513
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32412 Plasma immersion ion implantation
• CPC Class Codes: H01J 37/3266 Magnetic control means
• CPC Class Codes: H01J 37/32688 Multi-cusp fields

Abstract

A novel plasma treatment method (800, 814). The method includes forming an rf plasma discharge in a vacuum chamber. The plasma discharge includes an inductive coupling structure, which has a first cusp region at a first end of the structure and a second cusp region at a second end of the structure. In some embodiments, a third cusp region, which is between the first and second cusp regions, can also be included. The first cusp region is provided by a first electro-magnetic source and the second cusp region is provided by a second-electro magnetic source. The first electro-magnetic source and the second electro-magnetic source confines a substantial portion of the rf plasma discharge to a region away from a wall of the vacuum chamber. Accordingly, a plasma discharge is substantially a single ionic species (e.g., H₁+) can be formed.

Claims

1. A plasma treatment method comprising:

forming an rf plasma discharge in a vacuum chamber, said plasma discharge including an inductive coupling structure, said inductive coupling structure comprising a first cusp region at a first end of said structure and a second cusp region at a second end of said structure;

wherein said first cusp region is provided by a first electro-magnetic source and said second cusp region is provided by a second electro-magnetic source; and

wherein said first electro-magnetic source and said second electro-magnetic source confining a substantial portion of said rf plasma discharge to a region away from a wall of said vacuum chamber.

2. The method of claim 1 wherein said rf plasma discharge is provided by a single coil disposed overlying an upper surface of said vacuum chamber.

3. The method of claim 1 wherein said rf plasma discharge is provided by a plurality of coils, each of said coils being disposed overlying an upper surface of said vacuum chamber.

4. The method of claim 2 further comprising a tuning circuit coupled to said single coil.

5. The method of claim 1 wherein said first cusp is toward said a rf plasma source.

6. The method of claim 1 wherein said second cusp region is toward said susceptor.

7. The method of claim 1 further comprising applying a voltage bias between said rf plasma discharge and a workpiece to introduce partices in said rf plasma discharge into a surface of said workpiece.

8. The method of claim 1 further comprising providing a direct current from a direct current power supply to said first electro-magnetic source.

9. The method of claim 8 further comprising providing a direct current from a direct current power supply to said second electro-magnetic source.

10. The method of claim 9 wherein said first electro-magnetic source is coupled to said direct current power supply to current that flows in a first direction.

11. The method of claim 10 wherein said second electro-magnetic source is coupled to said direct current power supply to supply current that flows in a second direction, said second direction being opposite of said first direction.

12. The method of claim 1 further comprising feeding hydrogen gas into said vacuum chamber to form said rf plasma discharge comprising hydrogen bearing particles.

13. The method of claim 1 wherein said rf plasma discharge is a hydrogen bearing plasma.

14. The method of claim 1 wherein said rf plasma discharge is substantially a hydrogen bearing plasma of H₁⁺ particles.

15. The method of claim 1 further comprising providing a workpiece on a susceptor in said vacuum chamber.

16. The method of claim 11 further comprising accelerating particles from said rf plasma discharge into and through a surface of a work piece to a selected depth underlying said surface of said work piece.