Method for forming carbon nanotubes and carbon nanotube film forming apparatus

• US 9,059,178 B2
• Filed: 10/31/2012
• Issued: 06/16/2015
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Matsumoto, Takashi, Sugiura, Masahito, Koizumi, Kenjiro, Kashiwagi, Yusaku
• Primary Examiner(s): WIECZOREK, MICHAEL P
• Application Number:
  US13/665,724
• Publication Number:
  US 20130059091A1
• Time in Patent Office: 958 Days
• Field of Search: 427/534, 427/535, 427/539, 427/569, 427/575, 427/576, 977/842, 977/843, 977/844
• US Class Current: 1/1
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 32/16 Preparation
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/458 characterised by the method used for supporting substrates in the reaction chamber
• CPC Class Codes: C23C 16/503 using dc or ac discharges
• CPC Class Codes: C23C 16/511 using microwave discharges
• CPC Class Codes: H01L 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/76879 by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288
• CPC Class Codes: H01L 2221/1094 Conducting structures comprising nanotubes or nanowires
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/53276 containing carbon, e.g. fullerenes superconducting fullerenes H10N60/853
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method for forming carbon nanotubes includes preparing a target object having a surface on which one or more openings are formed, each of the openings having a catalyst metal layer on a bottom thereof; performing an oxygen plasma process on the catalyst metal layers; and activating the surfaces of the catalyst metal layers by performing a hydrogen plasma process on the metal catalyst layers subjected to the oxygen plasma process. The method further includes filling carbon nanotubes in the openings on the target object by providing an electrode member having a plurality of through holes above the target object in a processing chamber, and then growing the carbon nanotubes by plasma CVD on the activated catalyst metal layer by diffusing active species in a plasma generated above the electrode member toward the target object through the through holes while applying a DC voltage to the electrode member.

Claims

1. A method for forming carbon nanotubes, the method comprising:

preparing a target object to be processed having a surface on which one or more openings are formed, each of the openings having a catalyst metal layer on a bottom thereof;

agglomerating metal atoms in the catalyst metal layer by performing an oxygen plasma process on a surface of the catalyst metal layer such that migration of the metal atoms occurs on said surface of the catalyst metal layer;

activating the catalyst metal layer by performing a hydrogen plasma process on the catalyst metal layer subjected to the oxygen plasma process, to thereby reduce the catalyst metal layer oxidized by the oxygen plasma process;

substituting, after said activating, an atmosphere in which the target object is placed by a non-reactive gas; and

then

filling carbon nanotubes in the openings on the target object subjected to the oxygen plasma process and the hydrogen plasma process, wherein said filling is carried out by providing an electrode member having a plurality of through-holes above the target object in a processing chamber of a film forming apparatus and then growing the carbon nanotubes by plasma CVD on the activated catalyst metal layer by generating a plasma of a source gas in a space above the electrode member and diffusing active species in the plasma of the source gas toward the target object through the through-holes while applying a DC voltage to the electrode member, said non-reactive gas being employed as a carrier gas in said filling carbon nanotubes in the openings on the target object,

wherein said substituting the atmosphere in which the target object is placed and said filling carbon nanotubes in the openings on the target object are performed under processing pressures ranging from about 66.7 Pa to 400 Pa.

2. The method of claim 1, wherein a DC voltage ranging from about −

300 V to 0 V is applied to the electrode member.

3. The method of claim 1, wherein a diameter of the through-holes of the electrode member ranges from about 0.5 mm to 2 mm.

4. The method of claim 1, wherein, when the carbon nanotubes are grown, the target object is heated to about 350°

C. to 550°

C.

5. The method of claim 1, wherein the film forming apparatus includes:

a first gas inlet for introducing a plasma generating gas into the processing chamber; and

a second gas inlet for introducing the source gas into the processing chamber, the second gas inlet having a plurality of through-holes and being provided between the first gas inlet and the electrode member,

wherein a plasma of the plasma generating gas is generated in a space above the second gas inlet, and the plasma of the plasma generating gas passes through the through-holes of the second gas inlet and is mixed with the source gas in a space between the second gas inlet and the electrode member to generate the plasma of the source gas, and

wherein, after the source gas is mixed with the plasma of the plasma generating gas, the active species in the plasma of the source gas pass through the through-holes of the electrode member.

6. The method of claim 5, wherein a pulsed DC voltage is applied to the electrode member.

7. The method of claim 6, wherein at least one of said agglomerating, said activating and said filling includes applying a DC voltage to a mounting table on which the target object is mounted.

8. The method of claim 7, wherein a pulsed DC voltage is applied to the mounting table.

9. The method of claim 5, wherein at least one of said agglomerating, said activating and said filling includes applying a DC voltage to a mounting table on which the target object is mounted.

10. The method of claim 9, wherein a pulsed DC voltage is applied to the mounting table.

11. The method of claim 1, wherein the plasma used for the oxygen plasma process, the hydrogen plasma process and the carbon nanotube growing process is a microwave plasma.

12. The method of claim 11, wherein the microwave plasma is excited by a microwave introduced into the processing chamber by a planar antenna having a plurality of microwave radiation holes.

13. The method of claim 1, wherein the opening of the target object is a via hole or a wiring groove.

14. The method of claim 1, wherein the opening has a width ranging from about 10 nm to 300 nm.

15. The method of claim 1, wherein the oxygen plasma process, the hydrogen plasma process and the carbon nanotube growing process are successively performed in the same processing chamber.

16. The method of claim 1, wherein a pulsed DC voltage is applied to the electrode member.

17. The method of claim 16, wherein at least one of said agglomerating, said activating and said filling includes applying a DC voltage to a mounting table on which the target object is mounted.

18. The method of claim 17, wherein a pulsed DC voltage is applied to the mounting table.

19. The method of claim 1, wherein at least one of said agglomerating, said activating and said filling includes applying a DC voltage to a mounting table on which the target object is mounted.

20. The method of claim 19, wherein a pulsed DC voltage is applied to the mounting table.