Plasma generation for ion implanter

Patent metadata

Field	Value
Publication number	US-10163609-B2
Application number	US-201715475196-A
Country	US
Kind code	B2
Filing date	Mar 31, 2017
Priority date	Dec 15, 2016
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

An ion implanter comprises a dissociation chamber in the ion implanter. The dissociation chamber has an input port for receiving a gas and an output port for outputting ions. A vacuum chamber surrounds the dissociation chamber. A plurality of rods or plates of magnetic material are located adjacent to the dissociation chamber on at least two sides of the dissociation chamber. A magnet is magnetically coupled to the plurality of rods or plates of magnetic material. A microwave source is provided for supplying microwaves to the dissociation chamber, so as to cause electron cyclotron resonance in the dissociation chamber to ionize the gas.

First claim

What is claimed is:

1. An ion implanter, comprising:
a dissociation chamber in the ion implanter, the dissociation chamber having an input port for receiving a gas and an output port for outputting ions;
a vacuum chamber surrounding the dissociation chamber;
a plurality of rods or plates of magnetic material located adjacent to and extending through a wall of the dissociation chamber on at least two sides of the dissociation chamber;
a magnet magnetically coupled to the plurality of rods or plates of magnetic material, wherein the magnet is configured to induce a magnetic field in the magnetic material; and
a microwave source for supplying microwaves to the dissociation chamber, so as to cause electron cyclotron resonance in the dissociation chamber to ionize the gas.

2. The ion implanter of claim 1 , further comprising a housing, wherein the plurality of rods or plates are located between the housing and within the vacuum chamber.

3. The ion implanter of claim 2 , wherein the magnet is located outside the vacuum chamber.

4. The ion implanter of claim 3 , wherein a respective portion of each of the plurality of rods or plates extends beyond an end of the vacuum chamber, and the magnet is adjacent to the respective portion of each of the plurality of rods or plates.

5. The ion implanter of claim 1 , wherein the dissociation chamber has a metal grid covering the output port of the dissociation chamber, the grid having a grid size configured to absorb microwaves generated by the microwave source.

6. The ion implanter of claim 5 , wherein the grid comprises tungsten, niobium, molybdenum, tantalum, or rhenium.

7. The ion implanter of claim 1 , wherein the microwave source is a magnetron head coupled to the dissociation chamber by a microwave transmission medium.

8. The ion implanter of claim 1 , wherein the magnetic material includes at least one of the group consisting of CoFe, CoFeB, NiFe, and NiFeCo.

9. An ion implanter, comprising:
a dissociation chamber in the ion implanter, for dissociation of a gas into ions, the dissociation chamber having an input port for receiving the gas and an output port for outputting the ions;
a vacuum chamber surrounding the dissociation chamber;
a plurality of rods or plates of magnetic material located adjacent to and extending through a wall of the dissociation chamber on at least two sides of the dissociation chamber;
a magnet magnetically coupled to generate a magnetic field in the dissociation chamber; and
a microwave source for supplying microwaves to the dissociation chamber for causing electron cyclotron resonance in the dissociation chamber, wherein the microwaves have a frequency, and the dissociation chamber has a metal grid covering the output port of the dissociation chamber, the grid having a grid size configured to absorb microwaves having the frequency.

10. The ion implanter of claim 9 , wherein the grid comprises tungsten, niobium, molybdenum, tantalum, or rhenium.

11. The ion implanter of claim 9 , further comprising a plurality of plates of magnetic material, each plate having a first portion located adjacent to the dissociation chamber on a respective side of the dissociation chamber, and wherein the magnet is magnetically coupled to the a second portion of each plate of magnetic material.

12. The ion implanter of claim 11 , further comprising a housing, wherein the plurality of plates are located between the housing and the dissociation chamber.

13. The ion implanter of claim 12 , wherein each of the plurality of plates extends beyond an end of the vacuum chamber remote from the dissociation chamber, and the magnet is located outside of the housing, adjacent the end of each of the plurality of plates remote from the dissociation chamber.

14. The ion implanter of claim 9 , wherein the microwave source is a magnetron head electrically connected to a waveguide, the waveguide extending to the dissociation chamber.

15. The ion implanter of claim 9 , wherein the magnetic material includes at least one of the group consisting of CoFe, CoFeB, NiFe, and NiFeCo.

16. The ion implanter of claim 9 , wherein the magnet has a diameter greater than a diameter of the housing.

17. A method of implanting ions in a semiconductor substrate, comprising:
supplying gas to a dissociation chamber within a housing;
forming a magnetic field in the dissociation chamber using a magnet outside the housing and a plurality of rods or plates of magnetic material located adjacent to and extending through a wall of the dissociation chamber on at least two sides of the dissociation chamber, the magnet magnetically coupled to the dissociation chamber, wherein the magnet is configured to induce a magnetic field in the magnetic material;
supplying microwaves to the dissociation chamber, such that the microwaves and magnetic field cause dissociation of a gas by electron cyclotron resonance in the dissociation chamber to form a plasma; and
accelerating ions in the plasma, so the ions have a sufficient energy for implanting the ions in the semiconductor substrate.

18. The method of claim 17 , wherein the step of forming the magnetic field includes supplying the magnetic field from the magnet via a plurality of plates of the magnetic material located adjacent to the dissociation chamber on at least two sides of the dissociation chamber.

19. The method of claim 18 , wherein the magnetic field is provided to the dissociation chamber by rods or plates of the magnetic material extending from the magnet to a region within the housing and adjacent to the dissociation chamber.

20. The method of claim 17 , further comprising:
collecting plasma from the dissociation chamber to a plasma chamber; and
separating the microwaves from the plasma at an exit of the dissociation chamber.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Lin Tsung-Min
• Li Ming-Hsing
• Chien Fang-Chi
• Shih Chao-Li
• Chou Hong-Hsing

Classifications

• H10P30/20

  into semiconductor materials, e.g. for doping · CPC title

• H01J37/32412

  Plasma immersion ion implantation · CPC title

• H01J37/32229

  Waveguides · CPC title

• H01J37/32192

  Microwave generated discharge (H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence) · CPC title

• H01L21/265

  Electricity · mapped topic