# US 8,772,158 B2 · Multi-layer barrier layer stacks for interconnect structures

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- Number: US 8,772,158 B2
- Document ID: US8772158B2
- Status: Granted
- Kind: B2
- Application number: 13/770,026
- Filed: 2013-02-19
- Published: 2014-01-23
- Granted: 2014-07-08
- Earliest claimed: 2012-07-20
- Assignees: Globalfoundries Inc.
- Applicants: GLOBALFOUNDRIES Inc.
- Inventors: Vivian W. Ryan; Xunyuan Zhang; Paul R. Besser
- Web page: https://patentgrep.com/patent/US8772158B2

## CPC

- H10W 20/4403: {based on metals, e.g. alloys, metal silicides (H10W20/4484 takes precedence)}
- H10P 14/40: of conductive or resistive materials
- H10W 20/035: {combinations of barrier, adhesion or liner layers, e.g. multi-layered barrier layers}
- H10W 20/043: {for electroplating}
- H10W 20/049: {by diffusing alloying elements}
- H10W 20/0552: {by diffusing metallic dopants to react with dielectrics}
- H10W 20/064: {by modifying the conductivity of conductive parts, e.g. by alloying}
- H10W 20/425: {Barrier, adhesion or liner layers}
- H10W 42/121: {protecting against mechanical damage (H10W76/00, H10W74/00 take precedence)}
- H10W 70/611: {for connecting multiple chips together}
- H10W 70/635: {Through-vias}
- H10W 20/0425: {comprising multiple stacked seed or nucleation layers}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The present disclosure is generally directed to multi-layer barrier layer stacks for interconnect structures that may be used to reduce mechanical stress levels between the interconnect structure and a dielectric material layer in which the interconnect structure is formed. One illustrative method disclosed herein includes forming a recess in a dielectric layer of a substrate and forming an adhesion barrier layer including an alloy of tantalum and at least one transition metal other than tantalum to line the recess, wherein forming the adhesion barrier layer includes creating a first stress level across a first interface between the adhesion barrier layer and the dielectric layer. The method also includes forming a stress-reducing barrier layer including tantalum over the adhesion barrier layer, wherein the stress-reducing barrier layer reduces the first stress level to a second stress level less than the first stress level, and filling the recess with a fill layer.

## Claims

### Claim 1

A method, comprising:
forming a recess in a dielectric layer of a substrate;
forming an adhesion barrier layer comprising an alloy of tantalum and at least one transition metal other than tantalum to line the recess, wherein forming the adhesion barrier layer comprises creating a first stress level across a first interface between the adhesion barrier layer and the dielectric layer;
forming a stress-reducing barrier layer comprising tantalum over the adhesion barrier layer, wherein the stress-reducing barrier layer reduces the first stress level to a second stress level less than the first stress level; and
filling the recess with a fill layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein forming the stress-reducing barrier layer comprises creating a third stress level across a second interface between the stress-reducing barrier layer and the adhesion barrier layer, the third stress level being less than the second stress level.

### Claim 3 (depends on 1)

The method of claim 1, wherein the at least one transition metal comprises titanium.

### Claim 4 (depends on 1)

The method of claim 1, wherein the at least one transition metal comprises a plurality of transition metals other than tantalum.

### Claim 5 (depends on 1)

The method of claim 1, wherein filling the recess comprises forming a wetting layer above the stress-reducing barrier layer.

### Claim 6 (depends on 5)

The method of claim 5, wherein the wetting layer comprises ruthenium.

### Claim 7 (depends on 5)

The method of claim 5, further comprising annealing the substrate, wherein tantalum from the stress-reducing barrier layer diffuses into the wetting layer to form an alloy layer during the annealing.

### Claim 8 (depends on 7)

The method of claim 7, wherein the wetting layer comprises ruthenium.

### Claim 9 (depends on 1)

The method of claim 1, wherein the fill layer comprises copper.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
forming a first seed layer over the stress-reducing barrier layer to line the recess; and
forming a doped seed layer over the first seed layer, wherein the doped seed layer comprises a dopant not present in the first seed layer.

### Claim 11 (depends on 10)

The method of claim 10, wherein the dopant comprises manganese.

### Claim 12 (depends on 1)

The method of claim 1, wherein the adhesion barrier layer comprises tantalum nitride.

### Claim 13 (depends on 1)

The method of claim 1, wherein the recess comprises a trench.

### Claim 14 (depends on 1)

The method of claim 1, wherein the recess comprises a via opening.

### Claim 15

A method, comprising:
forming a recess in a dielectric layer of a substrate;
forming a first barrier layer above the dielectric layer to line the recess, the first barrier layer comprising an alloy of tantalum and at least one transition metal other than tantalum;
forming a second barrier layer over the first barrier layer, the second barrier layer comprising at least one of tantalum and tantalum nitride;
after forming the second barrier layer, forming a wetting layer above the second barrier layer;
filling the recess with a fill layer; and
after filling the recess, forming an alloy layer from the wetting layer by performing an annealing process on the substrate to diffuse at least one material component of one of the first and second barrier layers into at least a portion of the wetting layer.

### Claim 16 (depends on 15)

The method of claim 15, wherein the at least one transition metal comprises titanium.

### Claim 17 (depends on 15)

The method of claim 15, wherein the at least one transition metal comprises a plurality of transition metals other than tantalum.

### Claim 18 (depends on 15)

The method of claim 15, wherein the wetting layer comprises ruthenium.

### Claim 19 (depends on 15)

The method of claim 15, wherein the fill layer comprises copper.

### Claim 20 (depends on 15)

The method of claim 15, wherein the alloy layer comprises at least one of tantalum and titanium.

### Claim 21 (depends on 15)

The method of claim 15, wherein performing the annealing process comprises exposing the substrate to a heat treatment temperature from approximately 100-400° C. in a process ambient that comprises at least one of nitrogen and hydrogen.

### Claim 22 (depends on 15)

The method of claim 15, wherein forming the first barrier layer comprises depositing the first barrier layer on and in direct contact with the dielectric layer.

### Claim 23 (depends on 15)

The method of claim 15, wherein forming the second barrier layer comprises depositing the second barrier layer on and in direct contact with the first barrier layer.

### Claim 24 (depends on 15)

The method of claim 15, wherein forming the wetting layer comprises depositing the wetting layer on and in direct contact with the second barrier layer.

### Claim 25 (depends on 17)

The method of claim 17, wherein the at least one transition metal other than tantalum comprises chromium and zinc.

### Claim 26

A method, comprising:
forming a dielectric layer above a substrate;
forming a recess in the dielectric layer;
forming a first barrier layer by depositing a first material layer comprising an alloy of tantalum and at least one transition metal other than tantalum on and in direct contact with the dielectric layer, at least a first portion of the first barrier layer lining the entirety of sidewall and bottom surfaces of the recess, wherein forming the first barrier layer comprises creating a first stress level across a first interface between the first barrier layer and the dielectric layer;
forming a second barrier layer by depositing a second material layer comprising at least one of tantalum and tantalum nitride on and in direct contact with the first barrier layer, a least a second portion of the second barrier layer covering an entirety of the first portion of the first barrier layer, wherein forming the second barrier layer comprises reducing the first stress level across the first interface to a second stress level that is less than the first stress level;
after forming the second barrier layer, forming a wetting layer on and in direct contact with the second barrier layer, at least a third portion of the wetting layer covering an entirety of the second portion of the second barrier layer;
forming a conductive fill material above with the wetting layer, the conductive fill material completely filling a remaining portion the recess; and
after filling the recess, forming an alloy layer from the wetting layer by performing an annealing process on the substrate to diffuse at least one material component of at least the second barrier layer into at least an interface portion of the wetting layer.

### Claim 27 (depends on 26)

The method of claim 26, further comprising, prior to forming the conductive fill material, forming a seed layer stack on and in direct contact with the wetting layer, wherein the conductive fill material is formed on and in direct contact with the seed layer stack.

### Claim 28 (depends on 27)

The method of claim 27, wherein forming the seed layer stack comprises:
forming a first seed layer on and in direct contact with the wetting layer, at least a fourth portion of the first seed layer covering an entirety of the third portion of the wetting layer; and
forming a second seed layer above the first seed layer, at least a fifth portion of the second seed layer covering an entirety of the fourth portion of the first seed layer, wherein the second seed layer comprises a dopant material that is not present in the first seed layer.

### Claim 29 (depends on 28)

The method of claim 28, wherein the first and second seed layers comprise copper and the dopant material comprises one of manganese, aluminum, gold, calcium, zinc, cadmium, silver, and tin.

### Claim 30 (depends on 1)

The method of claim 1, wherein the at least one transition metal other than tantalum comprises chromium and zinc.