Formation of advanced interconnects including set of metal conductor structures in patterned dielectric layer

• US 10,115,670 B2
• Filed: 08/17/2016
• Issued: 10/30/2018
• Est. Priority Date: 08/17/2016
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Edelstein, Daniel C., Yang, Chih-Chao
• Primary Examiner(s): Mazumder, Didarul
• Application Number:
  US15/239,198
• Publication Number:
  US 20180053725A1
• Time in Patent Office: 804 Days
• Field of Search: 257752, 438626, 438631, 438645
• CPC Class Codes: H01L 21/2855 by physical means, e.g. sputtering, evaporation H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/28568 the conductive layers comprising transition metals H01L21/28518 takes precedence
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76856 by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
• CPC Class Codes: H01L 21/76858 by diffusing alloying elements
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/528 Geometry or layout of the interconnection structure H01L27/0207 takes precedence; algorithms G06F30/00
• CPC Class Codes: H01L 23/53209 based on metals, e.g. alloys, metal silicides H01L23/53285 takes precedence
• CPC Class Codes: H01L 23/53223 Additional layers associated with aluminium layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53247 Noble-metal alloys
• CPC Class Codes: H01L 23/53252 Additional layers associated with noble-metal layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53261 : Refractory-metal alloys
• CPC Class Codes: H01L 23/53266 : Additional layers associated with refractory-metal layers, e.g. adhesion, barrier, cladding layers

Abstract

A pattern is provided in a dielectric layer. The pattern includes a set of features in the dielectric for a set of metal conductor structures. The set of features have a first dimension. An adhesion promoting layer disposed over the patterned dielectric is deposited. A ruthenium layer disposed over the adhesion promoting layer is deposited. A cobalt layer is deposited over the ruthenium layer. A high temperature thermal anneal is performed which creates a ruthenium cobalt alloy layer to cover surfaces of the set of features. A metal layer is deposited disposed over the ruthenium cobalt alloy layer to form a set of metal conductor structures. In another aspect of the invention, a device is created using the method.

Claims

1. A method for fabricating an advanced metal conductor structure comprising:

providing a pattern in a dielectric layer, wherein the pattern includes a set of features in the dielectric layer for a set of metal conductor structures, the set of features having a first dimension;

creating an adhesion promoting layer disposed over the patterned dielectric layer;

depositing a ruthenium layer disposed on the adhesion promoting layer;

depositing a cobalt layer over the ruthenium layer;

performing a high temperature thermal anneal which creates a ruthenium cobalt alloy layer to cover surfaces of the set of features;

wherein a portion of the cobalt layer is unreacted with the ruthenium layer after the high temperature thermal anneal producing unreacted cobalt;

etching the unreacted cobalt from the ruthenium cobalt alloy layer; and

depositing a metal layer disposed on the ruthenium cobalt alloy layer to form the set of metal conductor structures.

2. The method as recited in claim 1, wherein the metal layer comprises a metal having a lower resistivity than cobalt at the first dimension.

3. The method as recited in claim 1, wherein the depositions of ruthenium layer and cobalt layer are performed by a physical vapor deposition process and a thickness of the ruthenium cobalt alloy layer is less than 10 Angstroms.

4. The method as recited in claim 1, wherein the adhesion promoting layer is comprised of a nitrogen enriched layer produced by a nitridation process and a liner layer comprised of one or more materials selected from the group consisting of Ta, Ti, W, TaN, TiN and WN.

5. The method as recited in claim 1, wherein the set of metal conductor structures is a set of conductive lines.

6. The method as recited in claim 1, wherein the high temperature thermal anneal is carried out in a temperature range between 300-800 degrees Centigrade in an N₂, H₂, He ambient or mixture thereof and the ruthenium cobalt alloy layer is formed.

7. The method as recited in claim 1, further comprising removing excess material on field areas of the dielectric layer using a planarization process.

8. The method as recited in claim 4, wherein the nitridation process is selected from the group of a plasma nitridation process and a thermal nitridation process.

9. The method as recited in claim 1, wherein the metal layer disposed over the ruthenium cobalt alloy layer is a copper layer.

10. The method as recited in claim 1, wherein the etching uses an etching process which is selective to the reacted cobalt as compared to the ruthenium cobalt alloy layer.

11. The method as recited in claim 10, wherein the etching uses a plasma etch process including a chemical containing fluorine or chlorine.

12. The method as recited in claim 1, wherein a thickness of the ruthenium cobalt alloy layer is between one and ten Angstroms.

13. The method as recited in claim 1, wherein the ruthenium layer is completely converted into the ruthenium cobalt alloy layer.

14. The method as recited in claim 1, wherein a portion of the ruthenium layer is unreacted after the high temperature thermal anneal and remains under the ruthenium cobalt layer and directly on the adhesion promoting layer.

15. The method as recited in claim 1, wherein a deposition of the ruthenium layer is conformal.