Method for forming metal film by ALD using beta-diketone metal complex

• US 8,133,555 B2
• Filed: 10/14/2008
• Issued: 03/13/2012
• Est. Priority Date: 10/14/2008
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Shinriki, Hiroshi, Jeong, Daekyun, Namba, Kunitoshi
• Primary Examiner(s): Yuan, Dah-Wei
• Assistant Examiner(s): Hernandez-Diaz, Jose
• Application Number:
  US12/251,343
• Publication Number:
  US 20100092696A1
• Time in Patent Office: 1,246 Days
• Field of Search: 427/255.28, 427/96.8, 427/97.2, 427/97.7, 427/576
• US Class Current: 427/576
• CPC Class Codes: C23C 16/18 from metallo-organic compounds
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions

Abstract

A method of forming a single-metal film on a substrate by plasma ALD includes: contacting a surface of a substrate with a β-diketone metal complex in a gas phase; exposing molecule-attached surface to a nitrogen-hydrogen mixed plasma; and repeating the above steps, thereby accumulating atomic layers to form a single-metal film on the substrate.

Claims

1. A method of forming a single-metal film on a substrate by plasma atomic layer deposition (ALD), comprising:

(i) contacting a surface of a substrate with a β

-diketone metal complex in a gas phase whereby molecules of the β

-diketone metal complex are attached to the surface of the substrate;

(ii) exposing the molecule-attached surface only to a nitrogen-hydrogen mixed plasma, thereby forming an atomic layer of the metal; and

(iii) repeating steps (i) and (ii) for a next atomic layer on top of the atomic layer in step (ii), thereby accumulating the atomic layers to form the single-metal film which is a virtually pure metal layer having a purity of at least 99% on the substrate,

wherein the nitrogen-hydrogen mixed plasma is produced by supplying a gas containing nitrogen and hydrogen, followed by applying RF power of 200 to 500 W having a frequency of 13.56 MHz to the gas,

wherein the gas containing nitrogen and hydrogen is a mixture of nitrogen gas and hydrogen gas wherein a volumetric ratio of nitrogen gas to hydrogen gas is 5/100 to 50/100.

2. The method according to claim 1, wherein the metal constituting the β

-diketone metal complex is selected from the group consisting of metals belonging to Group 8B, 1B, and 2B in the periodic chart.

3. The method according to claim 2, wherein the metal is selected from the group consisting of Ru, Co, Pd, Pt, and Ir.

4. The method according to claim 2, wherein the metal is Cu.

5. The method according to claim 1, wherein the β

-diketone metal complex is constituted by three β

-diketones coordinated to a metal in its molecule.

6. The method according to claim 1, wherein the β

-diketone metal complex has only β

-diketones coordinated to a metal in its molecule.

7. The method according to claim 1, further comprising forming a Cu film on the single-metal film.

8. The method according to claim 7, wherein the Cu film is formed by steps (i) to (iii) as a Cu seed layer.

9. The method according to claim 1, wherein steps (i) and (ii) are repeated at least 10 times.

10. The method according to claim 1, wherein steps (i) and (ii) are repeated until a thickness of the single-metal film reaches at least 0.4 to 0.5 nm.

11. The method according to claim 1, wherein the surface of the substrate on which the single-metal film is formed is constituted by a Cu barrier layer.

12. The method according to claim 1, wherein steps (i) and (ii) are conducted at a temperature of 300°

C. or lower.

13. The method according to claim 1, further comprising purging the β

-diketone metal complex gas after step (i) and purging the gas containing nitrogen and hydrogen after step (ii).

14. The method according to claim 1, wherein the β

-diketone metal complex is the only metal compound contacting the surface of the substrate in step (i).

15. The method according to claim 1, wherein the surface of the substrate on which the single-metal film is formed has trenches and the single-metal film covers the trenches as a comformal coating.

16. The method according to claim 1, wherein the metal in the β

-diketone metal complex is ruthenium.