High aspect ratio electroplated metal feature and method

• US 7,951,714 B2
• Filed: 02/16/2010
• Issued: 05/31/2011
• Est. Priority Date: 12/10/2007
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Hon Wong, Keith Kwong, Yang, Chih-Chao, Yang, Haining S., Edelstein, Daniel C.
• Primary Examiner(s): Richards; N Drew
• Assistant Examiner(s): Lee; Kyoung
• Application Number:
  US12/706,108
• Publication Number:
  US 20100143649A1
• Time in Patent Office: 469 Days
• Field of Search: None
• US Class Current: 438/687
• CPC Class Codes: C25D 5/02 Electroplating of selected surface areas
• CPC Class Codes: Y10T 428/24331 including nonapertured component
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

Disclosed are embodiments of an improved high aspect ratio electroplated metal structure (e.g., a copper or copper alloy interconnect, such as a back end of the line (BEOL) or middle of the line (MOL) contact) in which the electroplated metal fill material is free from seams and/or voids. Also, disclosed are embodiments of a method of forming such an electroplated metal structure by lining a high aspect ratio opening (e.g., a high aspect ratio via or trench) with a metal-plating seed layer and, then, forming a protective layer over the portion of the metal-plating seed layer adjacent to the opening sidewalls so that subsequent electroplating occurs only from the bottom surface of the opening up.

Claims

1. A metal structure comprising:

a substrate;

a dielectric layer adjacent said substrate;

an opening extending through said dielectric layer to said substrate, said opening having sidewalls and a bottom surface;

a metal-plating seed layer lining said opening and comprising a first portion adjacent said sidewalls and a second portion adjacent said bottom surface;

a protective layer adjacent said first portion of said metal-plating seed layer; and

an electroplated metal layer comprising one of a metal and a metal alloy adjacent said protective layer and said second portion of said metal-plating seed layer, said electroplated layer filling said opening and said protective layer comprising an additional metal layer having a metal-plating over-potential sufficient to prevent electroplating of said one of said metal and said metal alloy.

2. The metal structure of claim 1, said opening having an aspect ratio of said opening that is greater than approximately 6:

1.

3. The metal structure of claim 1, said metal-plating seed layer promoting electroplating of said one of said metal and said metal alloy.

4. The metal structure of claim 1, further comprising a barrier layer lining said opening between said metal-plating seed layer and said dielectric layer.

5. An interconnect structure comprising:

a substrate;

a dielectric layer adjacent said substrate;

an opening extending through said dielectric layer to said substrate, said opening having sidewalls and a bottom surface;

a copper-plating seed layer lining said opening and comprising a first portion adjacent said sidewalls and a second portion adjacent said bottom surface;

a protective layer adjacent said first portion of said copper-plating seed layer; and

an electroplated layer comprising one of copper and a copper alloy adjacent said protective layer and said second portion of said copper-plating seed layer, said electroplated layer fills said opening and said protective layer comprising an additional metal layer having a copper-plating over-potential sufficient to prevent electroplating of said one of said copper and said copper alloy.

6. The interconnect structure of claim 5, said opening having an aspect ratio that is greater than approximately 6:

1.

7. The interconnect structure of claim 5, said additional metal layer comprising one of tungsten, titanium, and chromium.

8. The interconnect structure of claim 5, further comprising a barrier layer lining said opening between said copper-plating seed layer and said dielectric layer.

9. An interconnect structure comprising:

a substrate;

a dielectric layer adjacent said substrate;

an opening extending through said dielectric layer to said substrate, wherein said opening has sidewalls and a bottom surface;

a barrier layer lining said opening;

an adhesion layer lining said opening above said barrier layer;

a copper-plating seed layer lining said opening above said adhesion layer, said copper-plating seed layer comprising a first portion adjacent said sidewalls and a second portion adjacent said bottom surface;

a protective layer adjacent said first portion of said copper-plating seed layer; and

an electroplated layer comprising one of copper and a copper alloy adjacent said protective layer and said second portion of said copper-plating seed layer, said electroplated layer filling said opening and being free from seams and voids and said protective layer comprising an additional metal layer having a copper-plating over-potential sufficient to prevent electroplating of said one of said copper and said copper alloy.

10. The metal structure of claim 9, said opening having an aspect ratio of said opening that is greater than approximately 6:

1.

11. The metal structure of claim 9, said metal-plating seed layer promoting electroplating of said one of said metal and said metal alloy.

12. The metal structure of claim 9, wherein said additional metal layer comprising any one of tungsten, titanium, and chromium.