IP Library › Granted Patent US 12685137

Granted Patent B2

US 12685137 · App. 18/073,119 · Granted Jul 14, 2026

Wire structure for low resistance interconnects

Inventors: Oscar van der Straten (Guilderland Center, NY); Koichi Motoyama (Clifton Park, NY); Chih-Chao Yang (Glenmont, NY)

Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION

H10W20/435 H10W20/033 H10W20/039 H10W20/056 H10W20/063 H10W20/425 H10W20/47

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Quick Facts

Patent No.: US 12685137
App. No.: 18/073,119
Granted: Jul 14, 2026
Kind: B2

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Abstract

Interconnect wire structures and techniques for fabrication thereof with uniform line profile and height are provided. In one aspect, a structure is provided that includes: a wafer; a first interlayer dielectric disposed on the wafer; a second interlayer dielectric disposed on the first interlayer dielectric; and an interconnect wire(s) embedded in the first interlayer dielectric and the second interlayer dielectric, where a first portion of a top half of the interconnect wire(s) has vertical sidewalls, and where a second portion of the top half of the interconnect wire(s) and a bottom half of the interconnect wire(s) have flared sidewalls. A first barrier layer and a (potentially different) second barrier layer can separate the bottom half and top half of the interconnect wire(s) from the first and second interlayer dielectrics. A method for forming the interconnect wire(s) is also provided.

Claims (40)

1 . A structure, comprising:

a wafer;

a first interlayer dielectric disposed on the wafer;

a second interlayer dielectric disposed on the first interlayer dielectric; and

at least one interconnect wire embedded in the first interlayer dielectric and the second interlayer dielectric,

wherein a first portion of a top half of the at least one interconnect wire has vertical sidewalls; a second portion of the top half of the at least one interconnect wire and a bottom half of the at least one interconnect wire have flared sidewalls; the first portion and the second portion of the top half of the at least one interconnect wire are both horizontally surrounded by the second interlayer dielectric; and the second interlayer dielectric is a layer of uniform dielectric material, and

wherein the bottom half of the at least one interconnect wire has a width W A , the first portion of the top half of the at least one interconnect wire has a width W B , and the second portion of the top half of the at least one interconnect wire has a width W C , wherein W A >W B , and wherein W C >W B .

2 . The structure of claim 1 , wherein the top half of the at least one interconnect wire is disposed directly on the bottom half of the at least one interconnect wire.

3 . The structure of claim 1 , wherein the bottom half of the at least one interconnect wire is embedded in the first interlayer dielectric, and wherein the top half of the at least one interconnect wire is embedded in the second interlayer dielectric.

4 . The structure of claim 3 , further comprising:

a first barrier layer separating the bottom half of the at least one interconnect wire from the first interlayer dielectric; and

a second barrier layer separating the top half of the at least one interconnect wire from the second interlayer dielectric.

5 . The structure of claim 4 , wherein the first barrier layer is present along the flared sidewalls of the bottom half of the at least one interconnect wire, and wherein the second barrier layer is present along the flared sidewalls of the top half of the at least one interconnect wire and along the vertical sidewalls of the second portion of the top half of the at least one interconnect wire.

6 . The structure of claim 4 , wherein the first barrier layer and the second barrier layer each comprises a material selected from the group consisting of: tantalum nitride (TaN), hafnium nitride (HfN), tantalum hafnium nitride (TaHfN), and combinations thereof.

7 . The structure of claim 1 , wherein the at least one interconnect wire comprises a material selected from the group consisting of: molybdenum (Mo), rhodium (Rh), ruthenium (Ru), tungsten (W), cobalt (Co), iridium (Ir), and combinations thereof.

8 . The structure of claim 1 , wherein the flared sidewalls of the bottom half of the at least one interconnect wire form an angle θ1 with a top surface of the wafer of from about 30 degrees to about 60 degrees, and wherein the flared sidewalls of the first portion of the top half of the at least one interconnect wire form an angle θ2 with a top surface of the first interlayer dielectric of from about 120 degrees to about 150 degrees.

9 . The structure of claim 8 , wherein the vertical sidewalls of the second portion of the top half of the at least one interconnect wire form an angle θ3 with a top surface of the second interlayer dielectric of about 90 degrees.

10 . A structure, comprising:

a wafer;

a first interlayer dielectric disposed on the wafer;

a second interlayer dielectric disposed on the first interlayer dielectric;

at least one interconnect wire embedded in the first interlayer dielectric and the second interlayer dielectric;

a first barrier layer separating a bottom half of the at least one interconnect wire from the first interlayer dielectric; and

a second barrier layer separating a top half of the at least one interconnect wire from the second interlayer dielectric, wherein a first portion of the top half of the at least one interconnect wire has vertical sidewalls, wherein a second portion of the top half of the at least one interconnect wire and the bottom half of the at least one interconnect wire have flared sidewalls, and wherein the first barrier layer has a different composition from the second barrier layer,

wherein the first barrier layer is in physical contact with the flared sidewalls of the bottom half of the at least one interconnect wire, and wherein the second barrier layer is in physical contact with the flared sidewalls of the second portion of the top half of the at least one interconnect wire and in physical contact with the vertical sidewalls of the first portion of the top half of the at least one interconnect wire.

11 . The structure of claim 10 , wherein the top half of the at least one interconnect wire is disposed directly on the bottom half of the at least one interconnect wire.

12 . The structure of claim 10 , wherein the bottom half of the at least one interconnect wire has a width W A , the first portion of the top half of the at least one interconnect wire has a width W B , and the second portion of the top half of the at least one interconnect wire has a width W C , wherein W A >W B , and wherein W C >W B .

13 . The structure of claim 10 , wherein the first barrier layer and the second barrier layer each comprises a different material selected from the group consisting of: TaN, HfN, TaHfN and combinations thereof.

14 . The structure of claim 10 , wherein the at least one interconnect wire comprises a material selected from the group consisting of: Mo, Rh, Ru, W, Co, Ir and combinations thereof.

15 . The structure of claim 10 , wherein the flared sidewalls of the bottom half of the at least one interconnect wire form an angle θ1 with a top surface of the wafer of from about 30 degrees to about 60 degrees, wherein the flared sidewalls of the first portion of the top half of the at least one interconnect wire form an angle θ2 with a top surface of the first interlayer dielectric of from about 120 degrees to about 150 degrees, and wherein the vertical sidewalls of the second portion of the top half of the at least one interconnect wire form an angle θ3 with a top surface of the second interlayer dielectric of about 90 degrees.

16 . The structure of claim 10 , wherein the first interlayer dielectric has a different composition from the second interlayer dielectric.

17 . A structure, comprising:

a wafer;

a first interlayer dielectric disposed on the wafer;

a second interlayer dielectric disposed directly on the first interlayer dielectric;

an interconnect wire embedded in the first interlayer dielectric and the second interlayer dielectric, wherein a first portion of a top half of the interconnect wire has vertical sidewalls, and wherein a second portion of the top half of the interconnect wire and a bottom half of the interconnect wire have flared sidewalls;

a first barrier layer directly next to the bottom half of the interconnect wire and in direct contact with the first interlayer dielectric; and

a second barrier layer directly next to the top half of the interconnect wire and in direct contact with the second interlayer dielectric, the second barrier layer being materially different from the first barrier layer.

18 . The structure of claim 17 , wherein the first portion and the second portion of the top half of the interconnect wire are both horizontally surrounded by the second interlayer dielectric, the second interlayer dielectric being a layer of uniform dielectric material that is materially different from the first interlayer dielectric.

19 . The structure of claim 17 , wherein the first barrier layer is in direct physical contact with the bottom half, from a top to a bottom thereof, of the interconnect wire and the second barrier layer is in direct physical contact with the top half, from a top to a bottom thereof, of the interconnect wire.