Critical dimension shrink through selective metal growth on metal hardmask sidewalls

Patent metadata

Field	Value
Publication number	US-9953916-B2
Application number	US-201715423923-A
Country	US
Kind code	B2
Filing date	Feb 3, 2017
Priority date	Jun 1, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A method for fabricating a self-aligned via structure includes forming a tri-layer mask on an ILD layer over a lower metal wiring layer, the tri-layer mask includes first and second insulating layers and a metal layer in between the insulating layers; defining a trench pattern through the first insulating layer and metal layer, the trench pattern having a first width; defining a first via pattern in a lithographic mask over the trench pattern, the first via pattern having a second width that is larger than the first width; growing a metal capping layer on an exposed sidewall of the trench pattern to decrease the first width to a third width that defines a second via pattern; transferring the trench pattern into the ILD layer to form a trench; and transferring the second via pattern through the ILD layer and into the metal wiring layer to form a via.

First claim

What is claimed is:

1. A self-aligned via structure, comprising:
a ILD layer disposed over a metal wiring layer;
a trench within the ILD layer, a bottom surface of the trench being substantially parallel to a top surface of the metal wiring layer and having a first width;
a via extending through the ILD layer and into a portion of the metal wiring layer, a vertical wall of the via oriented substantially perpendicular to the bottom surface of the trench and having a second width;
wherein the second width of the via is smaller than the first width of the trench.

2. The self-aligned via structure of claim 1 , further comprising a barrier metal lining the via and the trench within the ILD layer and the metal wiring layer.

3. The self-aligned via structure of claim 2 , further comprising copper filling the trench and the via.

4. The self-aligned via structure of claim 1 , wherein the first width is in a range from about 5 nm to about 50 nm.

5. The self-aligned via structure of claim 4 , wherein the second width is in a range from about 25 nm to about 70 nm.

6. The self-aligned via structure of claim 1 , wherein the metal wiring layer is copper or a copper alloy.

7. The self-aligned via structure of claim 1 , wherein the metal wiring layer is manganese, manganese alloys, cobalt, cobalt alloys, tungsten, tungsten alloys, or any combination thereof.

8. The self-aligned via structure of claim 1 , wherein the first width is in a range from about 10 nm to about 30 nm.

9. The self-aligned via structure of claim 1 , wherein the via and the trench further comprise a barrier metal layer liner and a copper filling.

10. The self-aligned via structure of claim 9 , wherein the barrier metal layer liner is tantalum, tantalum nitride, titanium nitride, titanium tungstate, or a combination thereof.

11. A self-aligned via structure, comprising:
a ILD layer disposed over a metal wiring layer;
a trench within through the ILD layer, a bottom surface of the trench being substantially parallel to a top surface of the metal wiring layer and having a first width;
a via extending through the ILD layer and into a portion of the metal wiring layer, a vertical wall of the via oriented substantially perpendicular to the bottom surface of the trench and having a second width;
wherein the second width of the via is smaller than the first width of the trench, and the trench and the via comprise a barrier metal layer and a metal.

12. The self-aligned via structure of claim 11 , further comprising a barrier metal lining the via and the trench within the ILD layer and the metal wiring layer.

13. The self-aligned via structure of claim 12 , further comprising copper filling the trench and the via.

14. The self-aligned via structure of claim 11 , wherein the first width is in a range from about 5 nm to about 50 nm.

15. The self-aligned via structure of claim 14 , wherein the second width is in a range from about 25 nm to about 70 nm.

16. The self-aligned via structure of claim 11 , wherein the metal wiring layer is copper or a copper alloy.

17. The self-aligned via structure of claim 11 , wherein the metal wiring layer is manganese, manganese alloys, cobalt, cobalt alloys, tungsten, tungsten alloys, or any combination thereof.

18. The self-aligned via structure of claim 11 , wherein the first width is in a range from about 10 nm to about 30 nm.

19. The self-aligned via structure of claim 11 , wherein the via and the trench further comprise a barrier metal layer liner and a copper filling.

20. The self-aligned via structure of claim 19 , wherein the barrier metal layer liner is tantalum, tantalum nitride, titanium nitride, titanium tungstate, or a combination thereof.

Assignees

• IBM

Inventors

• Chen Hsueh-Chung H
• He Hong
• Li Juntao
• Yang Chih-Chao
• Yin Yunpeng

Classifications

• H10P50/73 Primary

  using masks for insulating materials · CPC title

• H10W20/425

  Barrier, adhesion or liner layers · CPC title

• H10W20/089

  using processes for implementing desired shapes or dispositions of the openings, e.g. double patterning · CPC title

• H10W20/088

  involving partial etching of via holes · CPC title

• H10W20/087

  involving multiple stacked pre-patterned masks · CPC title