# US 7,745,282 B2 · Interconnect structure with bi-layer metal cap

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- Number: US 7,745,282 B2
- Document ID: US7745282B2
- Status: Granted
- Kind: B2
- Application number: 11/675,705
- Filed: 2007-02-16
- Published: 2008-08-21
- Granted: 2010-06-29
- Earliest claimed: 2007-02-16
- Assignees: International Business Machines Corporation
- Inventors: Chih-Chao Yang; Kaushik Chanda; Ping-Chuan Wang
- Web page: https://patentgrep.com/patent/US7745282B2

## CPC

- H10W 20/037: {the barrier, adhesion or liner layers being on top of a main fill metal}
- H10W 20/0372: {comprising multiple barrier, adhesion or liner layers}
- H10W 20/048: {by using plasmas or gaseous environments, e.g. by nitriding}
- H10W 20/056: {by filling conductive material into holes, grooves or trenches}
- H10W 20/074: {of dielectric parts comprising thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers}
- H10W 20/077: {on sidewalls or on top surfaces of conductors (H10W20/076 takes precedence)}
- H10W 20/096: {by contacting with gases, liquids or plasmas}
- H10W 20/425: {Barrier, adhesion or liner layers}
- H10W 20/063: {by forming conductive members before forming protective insulating material}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A structure and method of fabricating an interconnect structures with bi-layer metal cap is provided. In one embodiment, the method includes forming an interconnect feature in a dielectric material layer; and forming a bi-layer metallic cap on a top surface of the interconnect feature. The method further includes depositing a blanket layer of a dielectric capping layer, wherein the depositing covers an exposed surface of the dielectric material layer and a surface of the bi-layer metallic cap. The bi-layer metallic cap includes a metal capping layer formed on a conductive surface of the interconnect feature; and a metal nitride formed on a top portion of the metal capping layer. An interconnect structure is also described having an interconnect feature formed in a dielectric layer; a bi-layer metallic cap formed on a top portion of the interconnect feature; and a dielectric capping layer formed over the bi-layer metallic cap.

## Claims

### Claim 1

A method of fabricating an interconnect structure, the method comprising:
forming at least one interconnect feature in a dielectric material layer;
forming a bi-layer metallic cap on a top surface of said at least one interconnect feature;
wherein said forming said bi-layer metallic cap includes:
forming a metal capping layer on a conductive surface of said at least one interconnect feature; and
conducting a chemical plasma process for forming a metal nitride on a top portion of said metal capping layer; and
wherein a surface layer of said dielectric material layer is damaged during said chemical plasma process and further comprising removing said damaged surface layer.

### Claim 2 (depends on 1)

The method of fabricating an interconnect structure as recited in claim 1, further comprising depositing a blanket layer of a dielectric capping layer, wherein said depositing covers an exposed surface of said dielectric material layer and a surface of said bi-layer metallic cap.

### Claim 3 (depends on 1)

The method of fabricating an interconnect structure as recited in claim 1, wherein said metal capping layer includes a noble metal.

### Claim 4 (depends on 3)

The method of fabricating an interconnect structure as recited in claim 3, wherein said noble metal is selected from a group consisting of Co, Ir, Ru, Rh, Pd, Pt, Ta, W, B, P, MO, Re, and a combination thereof.

### Claim 5 (depends on 1)

The method of forming an interconnect structure as recited in claim 1, further comprising forming a hardmask on a top portion of said dielectric material, wherein said interconnect features is embedded within said dielectric material layer and said hardmask and further wherein said interconnect feature includes a conductive surface being coplanar with a top surface of said hardmask.

### Claim 6 (depends on 1)

The method of fabricating an interconnect structure as recited in claim 1, wherein said forming at least one interconnect feature includes:
forming at least one of a line and a via features in said dielectric material layer;
conformally depositing a barrier layer in said at least one of a line and a via; and
depositing a metal layer over said barrier layer.

### Claim 7 (depends on 6)

The method of fabricating an interconnect structure as recited in claim 6, wherein said metal layer is selected from a group consisting of Cu, W, Al and Cu alloys.

### Claim 8 (depends on 6)

The method of fabricating an interconnect structure as recited in claim 6, wherein said bi-layer metallic cap is formed within said at least one of a line and a via features.

### Claim 9 (depends on 6)

The method of fabricating an interconnect structure as recited in claim 6, further comprising partially etching said conductive material layer for forming a recessed top conductive surface, wherein said bi-layer metallic cap is formed on said recessed top conductive surface.

### Claim 10 (depends on 1)

The method of fabricating an interconnect structure as recited in claim 1, wherein said at least one interconnect feature includes a conductive surface coplanar with a top surface of said dielectric material layer and further wherein said metal capping layer is formed on said conductive surface.