Seed layer deposition

• US 6,824,665 B2
• Filed: 10/17/2001
• Issued: 11/30/2004
• Est. Priority Date: 10/25/2000
• Status: Expired due to Fees

• Current Assignee: Shipley Company, LLC (Dow, Inc.)
• Original Assignee: Shipley Company, LLC (Dow, Inc.)
• Inventors: Merricks, David, Dutkewych, Oleh B., Shelnut, James G., Shipley, Charles R.
• Primary Examiner(s): King, Roy
• Assistant Examiner(s): Leader, William T.
• Application Number:
  US09/978,797
• Publication Number:
  US 20020066671A1
• Time in Patent Office: 1,140 Days
• Field of Search: 205/102, 205/104, 205/123, 205/157, 205/191, 205/291, 205/916, 427/96, 427/305, 427/437, 427/443.1, 438/622, 438/627, 438/678, 438/687
• US Class Current: 205/102
• CPC Class Codes: C23C 18/1671 Electric field
• CPC Class Codes: C23C 18/38 Coating with copper
• CPC Class Codes: C23C 18/405 Formaldehyde
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76868 Forming or treating discontinuous thin films, e.g. repair, enhancement or reinforcement of discontinuous thin films
• CPC Class Codes: H01L 21/76874 for electroless plating
• CPC Class Codes: H01L 2221/1089 Stacks of seed layers
• CPC Class Codes: H05K 3/181 by electroless plating adhesives therefor H05K3/387
• CPC Class Codes: H05K 3/388 by the use of a metallic or inorganic thin film adhesion layer
• CPC Class Codes: H05K 3/422 characterised by electroless plating method; pretreatment therefor
• CPC Class Codes: Y10S 205/916 Sequential electrolytic and nonelectrolytic, or nonelectrolytic and electrolytic coating from the same bath

Abstract

Disclosed are methods for depositing a copper seed layer on a substrate having a conductive layer. Such methods are particularly suitable for depositing a copper seed layer on a substrate having small apertures, and preferably very small apertures.

Claims

1. A method for manufacturing an integrated circuit comprising the steps of:

providing an integrated circuit substrate comprising a discontinuous copper seed layer, a conductive layer and apertures of <

1 μ

m;

contacting the integrated circuit substrate with an electroless copper plating bath;

subjecting the electronic device substrate to a low current density for a period of time to initiate plating of copper on the conductive layer;

discontinuing the current; and

continuing to plate electrolessly to provide a substantially continuous copper seed layer;

wherein the electroless copper plating bath consists of a soluble form of copper ions, one or more reducing agents, water, one or more bases, optionally one or more complexing agents, and optionally one or more organic solvents.

2. The method of claim 1 wherein the conductive layer is a barrier layer.

3. The method of claim 2 wherein the barrier layer comprises cobalt, cobalt-tungsten-phosphorus, tungsten,tungsten nitride or titanium nitride.

4. The method of claim 1 wherein the current density is up to about 10 mA/cm².

5. The method of claim 4 wherein the current density is up to about 5 mA/cm².

6. The method of claim 1 wherein the period of time is up to about 30 seconds.

7. The method of claim 6 wherein the period of time is from about 10 to about 30 seconds.

8. The method of claim 1 wherein the substrate is a wafer.

9. A method of enhancing a discontinuous seed layer disposed on an integrated circuit substrate comprising the steps of:

contacting a substrate having a conductive layer, a discontinuous copper seed layer and apertures of <

1 μ

m with an electroless copper plating bath;

subjecting the substrate to a low current density for a period of time to initiate plating of copper on the conductive layer;

discontinuing the current; and

continuing to plate electrolessly to provide a substantially continuous copper seed layer, wherein the electroless copper plating bath consists of a soluble form of copper ions, one or more reducing agents, water, one or more bases, optionally one or more complexing agents, and optionally one or more organic solvents.

10. The method of claim 9 wherein current density is up to about 10 mA/cm².

11. The method of claim 10 wherein the current density is up to about 5 mA/cm².

12. The method of claim 9 wherein the period of time is up to about 30 seconds.

13. The method of claim 12 wherein the period of time is from about 10 to about 30 seconds.

14. The method of claim 9 wherein the substrate is a wafer.