Hollow cathode for plasma doping system

• US 6,182,604 B1
• Filed: 10/27/1999
• Issued: 02/06/2001
• Est. Priority Date: 10/27/1999
• Status: Expired due to Term

• Current Assignee: Varian Semiconductor Equipment Associates Incorporated (Applied Materials Incorporated)
• Original Assignee: Varian Semiconductor Equipment Associates Incorporated (Applied Materials Incorporated)
• Inventors: Fang, Ziwei, Goeckner, Matthew J.
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): Hassanzadeh, Parviz
• Application Number:
  US09/427,869
• Time in Patent Office: 468 Days
• Field of Search: 118/723.E, 118/723.FI, 118/723.CB, 118/723.FE, 118/723.ME, 118/723.R, 315/111.81, 315/111.21, 427/523, 427/355, 427/569, 204/298.05, 204/298.02, 204/298.04, 204/298.03, 204/298.01
• US Class Current: 118/723.00E
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: H01J 37/32596 Hollow cathodes
• CPC Class Codes: H01J 37/34 operating with cathodic sputtering H01J37/36 takes precedence ; methods of cathodic sputtering C23C14/34
• CPC Class Codes: H01J 37/3438 Electrodes other than cathode

Abstract

A plasma doping apparatus includes a hollow cathode to increase throughput and uniformity of ion implantations in a target. The hollow cathode is located adjacent an anode and a target cathode on which a target is placed. An ionizable gas is provided in a space between the anode and the target cathode. The space in which the ionizable gas is provided is surrounded by the hollow cathode. The hollow cathode has either a circular or rectangular cross-section.

Claims

1. A pulsed plasma processing system, comprising:

an anode;

a target cathode on which a first target is to be placed, the target cathode spaced apart from the anode; and

a hollow cathode disposed adjacent to each of the anode and the target cathode,

wherein the hollow cathode surrounds a portion of a space between the anode and the target cathode, and

wherein the entire hollow cathode is at one potential.

2. The system as recited in claim 1, wherein the hollow cathode comprises one of a circular, a rectangular and a multi-sided cross-section.

3. The system as recited in claim 1, further comprising a first high voltage pulse source having an output, wherein:

the anode is coupled to a reference voltage; and

the target cathode and the hollow cathode are each connected to the output of the first high voltage pulse source.

4. The system as recited in claim 3, further comprising an ionizable gas within the space surrounded by the hollow cathode.

5. The system as recited in claim 1, further comprising a first high voltage pulse source having a first output and a second high voltage pulse source having a second output, wherein:

the anode is coupled to a reference voltage;

the target cathode is coupled to the second output; and

the hollow cathode is coupled to the first output.

6. The system as recited in claim 1, further comprising a second target disposed on the hollow cathode.

7. A pulsed plasma processing system, comprising:

an enclosure;

an anode provided within the enclosure, the anode and enclosure coupled to a reference voltage;

a target cathode on which a first target is to be placed, the target cathode provided within the enclosure, spaced apart from the anode;

a hollow cathode disposed within the enclosure and adjacent to each of the anode and the target cathode, the hollow cathode to surround a portion of a space between the anode and the target cathode; and

a high voltage pulse source connected to the target cathode and the hollow cathode,

wherein the entire hollow cathode is at one potential.

8. The system as recited in claim 7, further comprising a second target disposed on the hollow cathode.

9. The system as recited in claim 7, wherein the hollow cathode comprises one of a circular, a rectangular and a multi-sided cross-section.

10. A pulsed plasma processing system, comprising:

a first anode;

a second anode spaced apart from and opposite to the first anode;

a hollow cathode disposed adjacent to the first and second anodes, the hollow cathode to surround a space between the first and second anodes; and

a first high voltage pulse source to supply a positive voltage pulse, relative to a reference voltage, to each of the first and second anodes;

wherein the hollow cathode is coupled to the reference voltage.

11. The apparatus as recited in claim 10, wherein the reference voltage is ground.

12. The apparatus as recited in claim 11, wherein:

a target wafer is positioned on the hollow cathode within the space between the first and second anodes.