ATOMIC COMPOSITION CONTROLLED RUTHENIUM ALLOY FILM FORMED BY PLASMA-ENHANCED ATOMIC LAYER DEPOSITION

• US 20100055433A1
• Filed: 08/29/2008
• Published: 03/04/2010
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Namba, Kunitoshi, Shinriki, Hiroshi, Jeong, Daekyun
• Granted Patent: US 8,084,104 B2
• Time in Patent Office: Days
• US Class Current: 428/220
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/4554 Plasma being used non-continuously in between ALD reactions C23C16/56 takes precedence
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76846 Layer combinations
• 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 metal film composed of multiple atomic layers continuously formed by atomic layer deposition of Ru and Ta or Ti includes at least a top section and a bottom section, wherein an atomic composition of Ru, Ta or Ti, and N varies in a thickness direction of the metal film. The atomic composition of Ru, Ta or Ti, and N in the top section is represented as Ru_(x1)Ta/Ti_(y1)N_(z1) wherein an atomic ratio of Ru_(x1)/(Ta/Ti_(y1)) is no less than 15, and z1 is 0.05 or less. The atomic composition of Ru, Ta or Ti, and N in the bottom section is represented as Ru_(x2)Ta/Ti_(y2)N_(z2) wherein an atomic ratio of Ru_(x2)/(Ta/Ti_(y2)) is more than zero but less than 15, and z2 is 0.10 or greater.

Claims

1. A metal film composed of multiple atomic layers continuously formed by atomic layer deposition of Ru and Ta or Ti, said metal film comprised of at least a top section and a bottom section, wherein

an atomic composition of Ru, Ta or Ti, and N varies in a thickness direction of the metal film,

the atomic composition of Ru, Ta or Ti, and N in the top section is represented as Ru_(x1)Ta/Ti_(y1)N_(z1) wherein an atomic ratio of Ru_(x1)/(Ta/Ti_(y1)) is no less than 15, and z1 is 0.05 or less, and

the atomic composition of Ru, Ta or Ti, and N in the bottom section is represented as Ru_(x2)Ta/Ti_(y2)N_(z2) wherein an atomic ratio of Ru_(x2)/(Ta/Ti_(y2)) is more than zero but less than 15, and z2 is 0.10 or greater.

2. The metal film according to claim 1, wherein 0.75≦

x1≦

1, 0≦

y1≦

0.05, 0≦

z1<

0.05, 0.02≦

x2≦

0.75, 0.05≦

y2≦

0.70, and 0.10≦

z2≦

0.25.

3. The metal film according to claim 1, wherein x1>

x2 and y2>

y1.

4. The metal film according to claim 1, wherein z2>

z1.

5. The metal film according to claim 1, wherein the atomic composition is substantially or nearly constant in the thickness direction in each of the top and bottom sections.

6. The metal film according to claim 1, wherein the top section and the bottom section have a thickness of 1 to 3 nm.

7. The metal film according to claim 1, which is further comprised of an intermediate section, wherein the atomic composition of Ru, Ta or Ti, and N in the intermediate section is represented as Ru_(x3)Ta/Ti_(y3)N_(z3) wherein an atomic ratio of Ru_(x3)/(Ta/Ti_(y3)) is less than one.

8. The metal film according to claim 7, wherein 0≦

x3≦

0.40, 0.40≦

y3≦

0.90, and 0.10≦

z3≦

0.25.

9. The metal film according to claim 7, wherein x1>

x2>

x3 and y3>

y2>

y1.

10. The metal film according to claim 7, wherein z2>

z1, and z3>

z1.

11. The metal film according to claim 7, wherein the top section, the intermediate section, and the bottom section have a thickness of 0.5 to 3 nm, 1 to 3 nm, and 0.5 to 3 nm, respectively.

12. The metal film according to claim 7, wherein the atomic composition is substantially or nearly constant in the thickness direction in each of the top, intermediate, and bottom sections.

13. The metal film according to claim 1, which is formed as a copper diffusion barrier metal film on a copper wiring layer and underneath a copper filling.

22. The method according to claim 1, wherein the substrate is a copper wiring substrate having trenches.

14. A method of forming a metal film on a substrate, comprising:

(i) placing a substrate in a reaction space;

(ii) conducting atomic layer deposition of Ta or Ti X times, each atomic deposition of Ta or Ti being accomplished by introducing a Ta or Ti source gas into the reaction space and applying a reducing gas plasma to the reaction space;

(iii) after step (ii), conducting atomic deposition of Ru Y times, each atomic deposition of Ru being accomplished by introducing a Ru source gas into the reaction space and applying a reducing gas plasma in the reaction space; and

(iv) repeating steps (ii) and (iii) Z times, thereby forming a metal film on the substrate;

wherein an atomic proportion of N in the metal film varies in a thickness direction of the metal film by changing a proportion of a hydrogen gas plasma in the reducing gas plasma within step (iii) or per step (iii) in step (iv).

15. The method according to claim 14, wherein step (iv) comprises (iva) repeating steps (ii) and (iii) Z1 times wherein a ratio of X/Y is defined as a first ratio, thereby forming a first section of the metal film, and (ivb) repeating steps (ii) and (iii) Z2 times using a second ratio of X/Y which is different from the first ratio, thereby forming a second section of the metal film, wherein atomic proportions of Ru, Ta or Ti, and N in the metal film vary in the thickness direction.

16. The method according to claim 14, wherein the reducing gas plasma in step (ii) is generated from a reducing gas including nitrogen.

17. The method according to claim 15, wherein the reducing gas plasma in step (iii) in step (iva) is generated from a reducing gas including both nitrogen and hydrogen, and as the step of changing the proportion of the hydrogen gas plasma, the reducing gas plasma in step (iii) in step (ivb) is generated from H₂ gas.

18. The method according to claim 15, wherein

the second ratio in step (ivb) is greater than the first ratio in step (iva),

step (iv) further comprises (ivc) repeating steps (ii) and (iii) Z3 times using a third ratio of X/Y which is smaller than the second ratio, and

the reducing gas plasma in step (iii) in steps (iva) and (ivb) is generated from a reducing gas including both nitrogen and hydrogen, and as the step of changing the proportion of the hydrogen gas plasma, the reducing gas plasma in step (iii) in step (ivc) is generated from H₂ gas.

19. The method according to claim 14, wherein the Ta or Ti source gas is an organic Ta source gas selected from the group consisting of TAIMATA (Tertiaryamylimidotris(dimethylamido)tantalum), TBTDET (Ta(N-i-C₄H₉)[N(C₂H₅)₂]₃), and PDMAT (Ta[N(CH₃)₂]₅).

20. The method according to claim 14, wherein the Ru source gas is a β

-diketone-coordinated ruthenium compound.

21. The method according to claim 14, wherein the Ru source gas is a Ru complex having a structure of Xa-Ru-Xb wherein Xa is a non-cyclic pentadienyl and Xb is a cyclopentadienyl.