Method for forming tantalum nitride film

• US 8,796,142 B2
• Filed: 03/03/2006
• Issued: 08/05/2014
• Est. Priority Date: 03/03/2005
• Status: Active Grant

• Current Assignee: Ulvac Incorporated
• Original Assignee: Ulvac Incorporated
• Inventors: Gonohe, Narishi, Toyoda, Satoru, Ushikawa, Harunori, Kondo, Tomoyasu, Nakamura, Kyuzo
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): GALVIN III, JOSEPH M
• Application Number:
  US11/885,345
• Publication Number:
  US 20090104775A1
• Time in Patent Office: 3,077 Days
• Field of Search: None
• US Class Current: 438/680
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• 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 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76859 by ion implantation
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• 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 tantalum nitride film rich in tantalum atoms is formed by simultaneously introducing a raw gas consisting of a coordination compound of elemental tantalum (Ta) having a coordinated ligand of formula: N═(R, R′) (wherein, R and R′ each represents an alkyl group having 1 to 6 carbon atoms) and NH₃ gas into a film-forming chamber; reacting the raw gas with the NH₃ gas; forming a reduced compound having Ta—NH₃ on a substrate; and introducing a hydrogen atom-containing gas into the chamber to form a tantalum nitride film rich in tantalum atoms. The resulting tantalum nitride film has a low resistance, low contents of C and N atoms, and a high compositional ratio: Ta/N, show sufficiently high adherence to Cu film and can thus be useful as a barrier film. Moreover, tantalum particles are implanted in the resulting film according to the sputtering technique to further enrich the film with tantalum.

Claims

1. A method for forming a tantalum nitride film comprising the steps:

using a composite type electrical connection film-forming apparatus equipped with a film-forming section comprising;

a film-forming chamber,

a sputtering device, and

an electrical connection film-forming chamber;

simultaneously introducing a raw gas comprising

a coordination compound comprising an elemental tantalum (Ta) having a coordinated ligand representable by the general formula;

N═

(R, R′

), and

NH₃ gas

into a film-forming chamber;

wherein R and R′

may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms,

reducing the raw gas with NH₃ gas and forming a reduced compound film on a substrate to thus partially remove the R or R′

groups bonded to the N atoms in the reduced compound film;

then introducing a hydrogen atom-containing gas without the raw gas into the chamber;

reacting the hydrogen atom-containing gas with the reduced compound film to form a tantalum nitride film rich in tantalum atoms;

implanting tantalum particles into the resulting tantalum nitride film according to a sputtering technique which makes use of a target containing tantalum as a principal constituent, while controlling a DC power and an RF power in such a manner that the DC power is set at a level of not more than 5 kW and the RF power is set at a value ranging from 400 to 800 W; and

forming an electrical connection-film, in the electrical connection film-forming chamber, on the tantalum nitride film thus obtained.

2. The method for forming a tantalum nitride film as set forth in claim 1, wherein

the hydrogen atom-containing gas is converted into radicals thereof by an action of heat or plasma within the film-forming chamber;

and

the resulting radicals are reacted with the reduced compound film to thus form a tantalum nitride film rich in tantalum atoms.

3. The method for forming a tantalum nitride film as set forth in claim 1, wherein

the raw gas is a gas comprising at least one coordination compound selected from the group consisting of penta-dimethylamino-tantalum, tert-amylimido-tris(dimethyl-amide) tantalum, penta-diethyl-amino-tantalum, tert-butylimido-tris(dimethylamide) tantalum, tert-butyl-imido-tris((ethyl-methyl-amide) tantalum, Ta(N(CH₃)₂)₃(N(CH₂CH₃)₂)₂ and TaX₅,

wherein X represents a halogen atom.

4. The method for forming a tantalum nitride film as set forth in claim 1, wherein

the hydrogen atom-containing gas is at least one gas selected from the group consisting of H₂, NH₃ and SiH₄.

5. The method for forming a tantalum nitride film as set forth in claim 1, wherein

a compositional ratio of tantalum to nitrogen in the tantalum nitride film satisfies Ta/N≧

2.0.

6. The method for forming a tantalum nitride film as set forth in claim 1, wherein

a compositional ratio of tantalum to nitrogen in the tantalum nitride film, in which the tantalum particles are implanted, Ta/N≦

2.0.

7. The method for forming a tantalum nitride film as set forth in claim 1, wherein

after implanting the tantalum particles, an adhesive layer is formed on the tantalum nitride film in the sputtering device and the electrical connection-film is formed, in the electrical connection film-forming chamber, on the adhesive layer.