Methods of forming cobalt silicide contact structures including sidewall spacers for electrical isolation and contact structures formed thereby

• US 20040038517A1
• Filed: 06/30/2003
• Published: 02/26/2004
• Est. Priority Date: 08/20/2002
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Hee-Sook, Moon, Kwang-Jin, Yang, Seung-Gil, Kang, Sang-Bum
• Application Number:
  US10/609,983
• Publication Number:
  US 20040038517A1
• Time in Patent Office: Days
• US Class Current: 438/630
• CPC Class Codes: H01L 21/28518 the conductive layers comprising silicides H01L21/28537 takes precedence
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners
• 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

Abstract

A contact structure is formed by forming an interlayer dielectric on a substrate having a semiconductive region. A contact hole is formed in the interlayer dielectric to expose the semiconductive region. A conductive structure is formed adjacent to the contact hole. Spacers are formed on inner sidewalls of the contact hole. A cobalt silicide layer is formed at a bottom of the contact hole. The spacers are configured to electrically isolate the cobalt silicide layer from the conductive structure. A conductive layer is formed on the cobalt silicide layer in the contact hole.

Claims

1. A method of fabricating a contact structure, comprising:

forming an interlayer dielectric on a substrate having a semiconductive region;

forming a contact hole in the interlayer dielectric to expose the semiconductive region;

forming spacers on inner sidewalls of the contact hole;

forming a cobalt silicide layer at a bottom of the contact hole; and

forming a conductive layer to fill the contact hole.

2. The method of claim 1, wherein the spacers comprise at least one of silicon oxide, silicon nitride, titanium nitride, tantalum nitride and boron nitride.

3. The method of claim 1, wherein each of the spacers has a respective thickness of about 100-1000 Å

.

4. The method of claim 1, wherein forming the cobalt silicide layer at the bottom of the contact hole comprises:

forming a cobalt layer on the exposed semiconductive region at the bottom of the contact hole, on sidewalls of the spacers, and on the interlayer dielectric; and

forming a barrier layer on the cobalt layer;

wherein the cobalt layer reacts with the substrate to form the cobalt silicide while the barrier layer is formed, and wherein the conductive layer is formed on the barrier layer.

5. The method of claim 4, wherein the cobalt layer and the barrier layer are formed in-situ in a same processing apparatus.

6. The method of claim 4, wherein the barrier layer comprises at least one of titanium nitride (TiN) and titanium/titanium nitride (Ti/TiN).

7. The method of claim 4, wherein forming the barrier layer on the cobalt layer comprises:

forming the barrier layer on the cobalt layer using chemical vapor deposition at a temperature of about 680-700°

C.

8. The method of claim 1, wherein forming the cobalt silicide layer at the bottom of the contact hole comprises:

forming a cobalt layer on the exposed semiconductiv region at the bottom of the contact hole, on sidewalls of the spacers, and on the interlayer dielectric;

thermally treating the cobalt layer to convert a first portion of the cobalt layer that is in contact with the semiconductiv region into a cobalt silicide layer; and

removing a second portion of the cobalt layer to expose the cobalt silicide at the bottom of the contact hole.

9. The method of claim 8, further comprising:

forming a barrier layer on the cobalt silicide layer, on the sidewalls of the spacers, and on the interlayer dielectric.

10. The method of claim 8, wherein the barrier layer comprises at least one of titanium nitride (TiN) and titanium/titanium nitride (Ti/TiN).

11. The method of claim 1, wherein forming the cobalt silicide layer at the bottom of the contact hole comprises:

sequentially forming a cobalt layer and a capping layer on the exposed semiconductiv region at the bottom of the contact hole, on sidewalls of the spacers, and on the interlayer dielectric;

thermally treating the cobalt layer to convert a first portion of the cobalt layer that is in contact with the semiconductiv region into a cobalt monosilicide layer;

removing a second portion of the cobalt layer and the capping layer to expose the cobalt monosilicide layer at the bottom of the contact hole; and

thermally treating the cobalt monosilicide layer to form a cobalt silicide layer.

12. The method of claim 11, further comprising:

forming a barrier layer on the cobalt silicide layer.

13. The method of claim 12, wherein the barrier layer comprises at least one of titanium nitride (TiN) or titanium/titanium nitride (Ti/TiN).

14. The method of claim 13, wherein forming the conductive layer comprises:

forming the conductive layer on the barrier layer.

15. The method of claim 1, further comprising:

planarizing the conductive layer until the interlayer dielectric is exposed.

16. A contact structure comprising:

an interlayer dielectric disposed on a substrate and having a contact hole formed therein that exposes a semiconductiv region of the substrate;

a cobalt silicide layer that is disposed at a bottom of the contact hole;

a pair of spacers that are respectively disposed on opposing sidewalls of the contact hole; and

a conductive layer that is disposed on the cobalt silicide layer in the contact hole.

17. The contact structure of claim 16, wherein a barrier layer is disposed between the spacers and the conductive layer.

18. The contact structure of claim 17, wherein the barrier layer comprises at least one of titanium nitride (TiN) and titanium/titanium nitride (Ti/TiN).

19. The contact structure as claimed in claim 16, wherein the spacers comprise at least one of silicon oxide, silicon nitride, titanium nitride, tantalum nitride and boron nitride.