Methods of forming an interconnect structure using a self-ending anodic oxidation

Patent metadata

Field	Value
Publication number	US-9812395-B2
Application number	US-201414507918-A
Country	US
Kind code	B2
Filing date	Oct 7, 2014
Priority date	Oct 7, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A method of forming low-k interconnect structure is disclosed, which comprises: providing at least one protruding structure on a substrate traversing between a first connection region to a second connection region defined thereon; performing anodic oxidation on the substrate having the protruding structure; forming one or more nanowire interconnect in the protruding structure traversing between the first connection region and the second connection region; the nanowire interconnect being surrounded by a dielectric layer formed during the anodic oxidation.

First claim

What is claimed is:

1. A method of forming an interconnect structure, comprising:
forming a protruding structure on a substrate traversing between a first connection region and a second connection region defined in the substrate, wherein the protruding structure is formed of a single material or a single compound material; and
oxidizing the protruding structure, wherein the oxidizing of the protruding structure forms a nanowire interconnect inside the protruding structure, the protruding structure being oxidized by performing a self-ending anodic oxidation on the substrate having the protruding structure,
the nanowire interconnect (i) being substantially surrounded by a dielectric layer formed by the anodic oxidation, the forming of the dielectric layer reaching a termination point without external interference, and (ii) traversing between the first connection region and the second connection region.

2. The method of claim 1 ,
wherein the provision of the protruding structure comprises forming a vertical type protruding structure,
wherein the vertical type protruding structure comprises an aspect ratio less than a threshold value in all in-plane directions.

3. The method of claim 1 ,
wherein the provision of the protruding structure comprises forming a horizontal type protruding structure,
wherein the horizontal type protruding structure comprises an aspect ratio greater than a threshold value in at least one in-plane direction.

4. The method of claim 1 ,
wherein the anodic oxidation of the protruding structure forms at least a nano channel in the protruding structure, extending substantially along the traversing direction of the nanowire interconnect.

5. The method of claim 4 ,
wherein the nano channel comprises air.

6. The method of claim 1 ,
wherein the anodic oxidation of the protruding structure forms a ridge structure under a lower portion thereof, extending substantially along the traversing direction of the nanowire interconnect.

7. The method of claim 1 ,
wherein a transverse cross-sectional profile of the protruding structure is arranged so that a lower portion thereof in connection with the substrate substantially oxidizes before an upper portion thereof.

8. The method of claim 1 , further comprising:
providing a mask layer on a surface of an upper portion of the protruding structure, the mask layer reducing an exposure of the upper portion in the anodic oxidation process, thereby reducing an oxidizing rate at the upper portion of the protruding structure.

9. The method of claim 1 ,
wherein the transverse cross-sectional profile of the protruding structure comprises at least one pair of local expansion and local contraction profiles, wherein the local contraction profile is arranged closer to the substrate than the local expansion profile.

10. The method of claim 1 , wherein the performing of the anodic oxidation on the substrate comprises:
using the substrate as part of an anode electrode.

11. The method of claim 1 , wherein the nanowire interconnect comprises a portion of the protruding structure.

12. A method of forming an interconnect structure, comprising:
forming a plurality of protruding structures on a substrate, the protruding structures traversing between a first connection region and a second connection region in the substrate, wherein each of the protruding structures is formed of a single material or a single compound material,
wherein the protruding structures are patterned adjacent to one another with a corresponding gap defined there-between; and

oxidizing a protruding structure of the plurality of protruding structures, wherein the oxidizing of the protruding structure forms a nanowire interconnect inside the protruding structure, the protruding structure being oxidized by performing a self-ending anodic oxidation on the substrate having the protruding structures,
the nanowire interconnect (i) being surrounded by a dielectric layer formed by the anodic oxidation, the forming of the dielectric layer reaching a termination point without external interference, and (ii) traversing between the first connection region and the second connection region.

13. The method of claim 12 ,
wherein the anodic oxidation causes an upper portion of each of the protruding structures to expand laterally outward toward an upper portion of an adjacent protruding structure, thereby defining at least one cavity having a low-K dielectric constant extending substantially along and between each pair of the adjacent protruding structures.

14. The method of 13 , further comprising:
selectively filling at least a portion of the at least one cavity with dielectric material.

15. The method of claim 12 , wherein the performing of the anodic oxidation on the substrate comprises:
using the substrate as part of an anode electrode.

16. The method of claim 12 , wherein the nanowire interconnect comprises a portion of the protruding structure of the plurality of protruding structures.

17. A method of forming an interconnect structure, comprising:
forming a protruding structure on a substrate traversing between a first connection region and a second connection region defined in the substrate, wherein the protruding structure is formed of a single material or a single compound material; and
oxidizing the protruding structure, wherein the oxidizing of the protruding structure forms a nanowire interconnect inside the protruding structure, the protruding structure being oxidized by performing a self-ending anodic oxidation on the substrate having the protruding structure,
the nanowire interconnect (i) being substantially surrounded by a dielectric layer formed by the anodic oxidation, the forming of the dielectric layer reaching a termination point without external interference, and (ii) traversing between the first connection region and the second connection region,
wherein the anodic oxidation of the protruding structure forms at least a substantially vacuum nano channel in the protruding structure, extending substantially along the traversing direction of the nanowire interconnect.

18. The method of claim 17 ,
wherein the provision of the protruding structure comprises forming a vertical type protruding structure,
wherein the vertical type protruding structure comprises an aspect ratio less than a threshold value in all in-plane directions.

19. The method of claim 17 ,
wherein the provision of the protruding structure comprises forming a horizontal type protruding structure,
wherein the horizontal type protruding structure comprises an aspect ratio greater than a threshold value in at least one in-plane direction.

20. The method of claim 17 ,
wherein the anodic oxidation of the protruding structure forms a ridge structure under a lower portion thereof, extending substantially along the traversing direction of the nanowire interconnect.

21. The method of claim 17 ,
wherein a transverse cross-sectional profile of the protruding structure is arranged so that a lower portion thereof in connection with the substrate substantially oxidizes before an upper portion thereof.

22. The method of claim 17 , further comprising:
providing a mask layer on a surface of an upper portion of the protruding structure, the mask layer reducing an exposure of the upper portion in the anodic oxidation process, thereby reducing an oxidizing rate at the upper portion of the protruding structure.

23. The method of claim 17 , wherein the perfo

Assignees

• Taiwan Semiconductor Mfg Co Ltd
• Univ Nat Taiwan
• Taiwan Semiconductor Mfg Company Ltd & Nat Taiwan Univ

Inventors

• Hwu Jenn-Gwo
• Tian Wei-Cheng
• Pan Samuel C
• Wang Chao-Hsiung
• Liu Chi-Wen

Classifications

• H10W20/0554

  of nanotubes or nanowires · CPC title

• H10W20/435

  Cross-sectional shapes or dispositions of interconnections · CPC title

• H10W20/072

  of dielectric parts comprising air gaps · CPC title

• H10W20/071

  of dielectric parts thereof · CPC title

• H10W20/065

  by making at least a portion of the conductive part non-conductive, e.g. by oxidation · CPC title