Cobalt top layer advanced metallization for interconnects

• US 9,716,063 B1
• Filed: 08/17/2016
• Issued: 07/25/2017
• 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): Stark, Jarrett
• Application Number:
  US15/239,139
• Time in Patent Office: 342 Days
• 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 21/76802 by forming openings in dielectrics
• 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 21/76847 the layer being positioned within the main fill metal
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/7685 the layer covering a conductive structure H01L21/76849 takes precedence
• 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 21/76882 Reflowing or applying of pressure to better fill the contact hole
• 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 23/53252 : Additional layers associated with noble-metal layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53261 : Refractory-metal alloys

Abstract

A pattern is provided in a dielectric layer in which a set of features are patterned for a set of metal conductor structures. An adhesion promoting layer is created disposed over the patterned dielectric. A metal layer is deposited to fill a first portion of the set of features disposed the adhesion promoting layer. A ruthenium layer is deposited disposed over the metal layer. Using a physical vapor deposition process, a cobalt layer is deposited disposed over the ruthenium layer. A thermal anneal reflows the cobalt layer to fill a second portion of the set of features. In another aspect of the invention, a device created by the method is described.

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 for a set of metal conductor structures;

creating an adhesion promoting layer disposed over the patterned dielectric;

depositing a metal layer to fill a first portion of the set of features disposed the adhesion promoting layer;

depositing a ruthenium layer disposed over the metal layer;

nitridizing the ruthenium layer using a nitridation process which nitridizes at least a surface portion of the ruthenium layer;

using a physical vapor deposition process to deposit a cobalt layer disposed over the ruthenium layer; and

performing a thermal anneal which reflows the cobalt layer to fill a second portion of the set of features.

2. The method as recited in claim 1, wherein the adhesion promoting layer is a liner layer.

3. The method as recited in claim 1, wherein the adhesion promoting layer is a nitrogen enriched layer produced by a nitridation process.

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 are a set of conductive lines.

6. The method as recited in claim 2, wherein the thermal anneal is carried out in a temperature range between 300-800 degrees Centigrade in a neutral ambient and a RuCo alloy 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 3, wherein the nitridation process which creates the nitrogen enriched layer is selected from the group of a plasma nitrididation process and a thermal nitridation process.