Critical dimension shrink through selective metal growth on metal hardmask sidewalls

Patent metadata

Field	Value
Publication number	US-10168075-B2
Application number	US-201815907812-A
Country	US
Kind code	B2
Filing date	Feb 28, 2018
Priority date	Jun 1, 2015
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

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:
an inter-level dielectric (ILD) layer arranged on a metal wiring layer;
a trench arranged within the ILD layer;
a via arranged substantially perpendicular to the trench and extending through an area of the trench, the via further extending into a portion of the metal wiring layer; and
a metal capping layer lining sidewalls of the via at the area where the via extends through the trench.

2. The self-aligned via structure of claim 1 , wherein the metal capping layer has a thickness of about 1 nm to about 10 nm.

3. The self-aligned via structure of claim 1 , further comprising a metal filling the trench and the via.

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

5. The self-aligned via structure of claim 4 , wherein the via has a width that is less than the trench.

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

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

8. 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.

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 dual damascene structure, comprising:
a trench arranged within an inter-level dielectric (ILD) layer; and
a via arranged substantially perpendicular to the trench, self-aligned with the trench, and extending through an area of the trench, the via further extending through the ILD layer and into a portion of a metal wiring layer beneath the ILD layer;
wherein the via has a width that is less than the trench at the area that extends through with the trench.

12. The dual damascene 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 dual damascene structure of claim 12 , further comprising copper filling the trench and the via.

14. The dual damascene structure of claim 11 , wherein the trench has a width in a range from about 5 nm to about 50 nm.

15. The dual damascene structure of claim 11 , wherein the metal wiring layer is copper.

16. The dual damascene structure of claim 11 , wherein the metal wiring layer is a copper alloy.

17. The dual damascene 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 dual damascene structure of claim 11 , wherein the via and the trench further comprise a barrier metal layer liner and a copper filling.

19. The dual damascene structure of claim 18 , wherein the barrier metal layer is tantalum nitride.

20. The dual damascene structure of claim 19 , wherein the barrier metal layer liner is tantalum, 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