Atomic layer deposition of tungsten materials

• US 7,964,505 B2
• Filed: 05/15/2008
• Issued: 06/21/2011
• Est. Priority Date: 01/19/2005
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Wu, Kai, Khandelwal, Amit, Gelatos, Avgerinog V., Moorthy, Madhu
• Primary Examiner(s): Garber; Charles D
• Assistant Examiner(s): Isaac; Stanetta D
• Application Number:
  US12/121,209
• Publication Number:
  US 20090053893A1
• Time in Patent Office: 1,132 Days
• Field of Search: 438/677, 438/680, 257/E21.171, 257/E21.585
• US Class Current: 438/680
• CPC Class Codes: C23C 16/0281 of metallic sub-layers C23C16/029 takes precedence
• CPC Class Codes: C23C 16/08 from metal halides
• CPC Class Codes: C23C 16/14 Deposition of only one other metal element
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• 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 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76856 by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
• CPC Class Codes: H01L 21/7687 Thin films associated with contacts of capacitors
• CPC Class Codes: H01L 21/76876 for deposition from the gas phase, e.g. CVD
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 2221/1089 Stacks of seed layers

Abstract

Embodiments of the invention provide an improved process for depositing tungsten-containing materials. The process utilizes soak processes and vapor deposition processes, such as atomic layer deposition (ALD) to provide tungsten films having significantly improved surface uniformity and production level throughput. In one embodiment, a method for forming a tungsten-containing material on a substrate is provided which includes positioning a substrate within a process chamber, wherein the substrate contains an underlayer disposed thereon, exposing the substrate sequentially to a tungsten precursor and a reducing gas to deposit a tungsten nucleation layer on the underlayer during an ALD process, wherein the reducing gas contains a hydrogen/hydride flow rate ratio of about 40:1, 100:1, 500:1, 800:1, 1,000:1, or greater, and depositing a tungsten bulk layer on the tungsten nucleation layer. The reducing gas contains a hydride compound, such as diborane, silane, or disilane.

Claims

1. A method for forming a tungsten-containing material on a substrate, comprising:

positioning a substrate within a process chamber, wherein the substrate comprises an underlayer disposed thereon;

exposing the substrate sequentially to a tungsten precursor and a reducing gas to deposit a tungsten nucleation layer on the underlayer during an atomic layer deposition process, wherein the reducing gas comprises a hydrogen/hydride flow rate ratio of about 500;

1 or greater; and

depositing a tungsten bulk layer on the tungsten nucleation layer.

2. The method of claim 1, wherein the reducing gas comprises a hydride compound selected from the group consisting of silane, disilane, diborane, phosphine, derivatives thereof, and combinations thereof.

3. The method of claim 2, wherein the reducing gas comprises diborane.

4. The method of claim 2, wherein the reducing gas comprises silane or disilane.

5. The method of claim 1, wherein the hydrogen/hydride flow rate ratio of the reducing gas is about 800:

1 or greater.

6. The method of claim 5, wherein the hydrogen/hydride flow rate ratio of the reducing gas is about 1,000:

1 or greater.

7. The method of claim 1, wherein the hydride compound comprises a flow rate within a range from about 1 sccm to about 40 sccm.

8. The method of claim 7, wherein the reducing gas comprises hydrogen having a flow rate within a range from about 1 slm to about 20 slm.

9. The method of claim 8, wherein the flow rate of the hydride compound is within a range from about 3 sccm to about 30 sccm and the hydrogen comprises a flow rate within a range from about 3 slm to about 15 slm.

10. The method of claim 9, wherein the flow rate of the hydride compound is within a range from about 5 sccm to about 15 sccm and the hydrogen comprises a flow rate within a range from about 5 slm to about 10 slm.

11. The method of claim 1, wherein the substrate is heated to a temperature within a range from about 350°

C. to about 420°

C.

12. The method of claim 1, further comprising exposing the underlayer to a pre-soak gas comprising the reducing agent during a pre-soak process, wherein the underlayer is exposed to the reducing agent for a time period within a range from about 5 seconds to about 60 seconds.

13. The method of claim 12, wherein the time period is within a range from about 10 seconds to about 30 seconds.

14. The method of claim 1, further comprising exposing the tungsten nucleation layer to a post-soak gas comprising the reducing agent during a post-soak process, wherein the tungsten nucleation layer is exposed to the reducing agent for a time period within a range from about 5 seconds to about 60 seconds.

15. The method of claim 14, wherein the time period is within a range from about 10 seconds to about 30 seconds.

16. The method of claim 1, wherein the tungsten bulk layer has a resistivity measured across the substrate of about 10 μ

Ω

-cm or less.

17. The method of claim 16, wherein the resistivity is about 8 μ

Ω

-cm or less.

18. The method of claim 1, wherein the underlayer is a barrier layer and comprises a material selected from the group consisting of metallic titanium, titanium nitride, metallic tantalum, tantalum nitride, ruthenium, nickel, cobalt, metallic tungsten, tungsten nitride, silicides thereof, derivatives thereof, alloys thereof, and combinations thereof.

19. The method of claim 18, wherein the tungsten bulk layer is deposited by a chemical vapor deposition process.

20. A method for forming a tungsten-containing material on a substrate, comprising:

positioning a substrate within a process chamber, wherein the substrate comprises an underlayer disposed thereon;

exposing the substrate sequentially to a tungsten precursor and a reducing gas to deposit a tungsten nucleation layer on the underlayer during an atomic layer deposition process, wherein the reducing gas comprises a hydrogen/diborane flow rate ratio of about 100;

1 or greater; and

depositing a tungsten bulk layer on the tungsten nucleation layer.

21. The method of claim 20, wherein the hydrogen/diborane flow rate ratio of the reducing gas is about 800:

1 or greater.

22. A method for forming a tungsten-containing material on a substrate, comprising:

positioning a substrate within a process chamber, wherein the substrate comprises an underlayer disposed thereon;

exposing the underlayer to a pre-soak gas comprising diborane during a pre-soak process;

exposing the substrate sequentially to a tungsten precursor and a reducing gas to deposit a tungsten nucleation layer on the underlayer during an atomic layer deposition process, wherein the reducing gas comprises a hydrogen/diborane flow rate ratio of about 100;

1 or greater;

exposing the substrate to a post-soak gas comprising diborane during a post-soak process; and

depositing a tungsten bulk layer on the tungsten nucleation layer.

23. The method of claim 22, wherein the hydrogen/diborane flow rate ratio of the reducing gas is about 500:

1 or greater.

24. The method of claim 23, wherein the hydrogen/diborane flow rate ratio of the reducing gas is about 800:

1 or greater.