Low resistivity tantalum

• US 6,339,258 B1
• Filed: 07/02/1999
• Issued: 01/15/2002
• Est. Priority Date: 07/02/1999
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cooney, Edward Crandal III, Uzoh, Cyprian Emeka
• Primary Examiner(s): Clark, Jhihan B.
• Application Number:
  US09/347,221
• Time in Patent Office: 928 Days
• Field of Search: 257/762, 257/750, 257/751, 257/758, 438/627, 438/643, 438/653, 438/927, 438/687
• US Class Current: 257/762
• CPC Class Codes: H01L 23/53233 Copper alloys
• 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

An alpha-phase tantalum having a resistivity of about 15 micro-ohm-cm or less is provided and is especially useful as a barrier layer for copper and copper alloy interconnections.

Claims

1. Alpha-phase tantalum having a resistivity of less than 15 micro-ohm-cm.

2. The alpha-phase tantalum of claim 1 having a <

110>

diffraction peak at about 49°

(2-theta) as measured by x-ray diffraction using monochromatic iron radiation from a sealed tube source operating at 35 kilovolts and 35 milliamps.

3. The alpha-phase tantalum of claim 2 having the x-ray diffraction spectra as shown in FIG. 2.

4. An interconnection structure for semiconductor integrated circuits which comprises a layer of copper or copper alloy and a barrier layer of alpha-phase tantalum having a resistivity of less than 15 micro-ohm-cm.

5. The interconnection structure of claim 4 wherein the alpha-phase tantalum has a <

110>

diffraction peak at about 45°

(2-theta) obtained by an x-ray diffraction scan using monochromatic iron radiation from a sealed tube source operating at 35 kilovolts and 35 milliamps.

6. The interconnection structure of claim 4 wherein the alpha-phase tantalum has an x-ray diffraction scan shown in FIG. 2.

7. The interconnection structure of claim 4 which further includes electrical isolation and wherein the barrier layer separates the copper from the isolation.

8. The interconnection structure of claim 4 wherein the thickness of the copper is about 200 to about 1500 Å

.

9. The interconnection structure of claim 4 wherein the thickness of the alpha-phase tantalum layer is about 50 to about 300 Å

.

10. The interconnection structure of claim 7 which further includes a second barrier layer between the insulation and the alpha-phase tantalum.

11. The interconnection structure of claim 10 wherein the second barrier layer is selected from the group consisting of tantalum nitride, tantalum silicon, tantalum silicon nitride, titanium nitride, tungsten and tungsten nitride.

12. The interconnection structure of claim 10 wherein the second barrier layer is tantalum nitride or titanium nitride.

13. The interconnection structure of claim 10 wherein the second barrier layer is tantalum nitride.

14. The interconnection structure of claim 10 wherein the thickness of the second barrier layer is about 25 to about 300 Å

.

15. An interconnection structure for semiconductor integrated circuits which comprises a layer of copper or copper alloy and a barrier layer of alpha-phase tantalum having a resistivity of about 15 micro-ohm-cm or less, and

wherein the thickness of the copper is about 200 to about 1500 Å

.

16. An interconnection structure for semiconductor integrated circuits which comprises a layer of copper or copper alloy and a barrier layer of alpha-phase tantalum having a resistivity of about 15 micro-ohm-cm or less, and

wherein the thickness of the alpha-phase tantalum layer is about 50 to about 300 Å

.

17. The interconnection structure of claim 16 wherein the thickness of the copper is about 200 to about 1500 Å

.