Seed layer recovery

• US 20020074242A1
• Filed: 10/13/2001
• Published: 06/20/2002
• Est. Priority Date: 10/13/2000
• Status: Abandoned Application

• Current Assignee: Shipley Company, LLC (Dow, Inc.)
• Original Assignee: Shipley Company, LLC (Dow, Inc.)
• Inventors: Calvert, Jeffrey M., Beica, Rozalia, Morrissey, Denis
• Application Number:
  US09/977,596
• Publication Number:
  US 20020074242A1
• Time in Patent Office: Days
• US Class Current: 205/704
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• 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 21/76861 Post-treatment or after-treatment not introducing additional chemical elements into the layer
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 21/76874 for electroless plating

Abstract

Disclosed is a method for repairing of seed layers by removal of oxidized metal from the seed layers prior to subsequent metallization. Also disclosed is a method for monitoring such repair to provide substantially metal oxide free seed layers.

Claims

1. A method of removing oxidized metal from a metal seed layer comprising the steps of:

a) contacting a metal seed layer containing oxidized metal disposed on a substrate with an aqueous solution having a pH maintained in the range of about 6.5 to about 13;

b) subjecting the solution to a voltage of from about 0.1 to 5 volts to reduce the oxidized metal; and

c) monitoring the reduction of the oxidized metal to provide a seed layer substantially free of all oxidized metal species.

2. The method of claim 1 wherein the pH is maintained by a buffer.

3. The method of claim 2 wherein the buffer comprises phosphate, boric acid/borate, tris(hydroxymethyl)aminomethane hydrohalide salt or carbonate.

4. The method of claim 1 wherein the pH of the aqueous solution is maintained in the range of about 7 to about 10.

5. The method of claim 1 wherein the metal seed layer comprises copper or copper alloys.

6. The method of claim 1 wherein the voltage is in the range of 0.2 to 5 volts.

7. The method of claim 6 wherein the voltage is in the range of 1 to 5 volts.

8. The method of claim 1 wherein the voltage is applied to the metal seed layer for 5 to 300 seconds.

9. The method of claim 1 wherein the substrate is selected from semiconductor wafers and dielectric layers.

10. The method of claim 1 wherein a potentiostat is used to monitor the reduction of the oxidized metal.

11. A method for manufacturing an electronic device comprising the steps of:

a) contacting a metal seed layer containing oxidized metal disposed on a substrate with an aqueous solution having a pH maintained in the range of about 6.5 to about 13;

b) subjecting the solution to a voltage of from about 0.1 to 5 volts to reduce the oxidized metal;

c) monitoring the reduction of the oxidized metal to provide a substantially metal oxide free seed layer; and

d) contacting the substantially metal oxide free seed layer with an electroplating bath.

12. The method of claim 11 wherein the pH is maintained by a buffer.

13. The method of claim 12 wherein the buffer comprises phosphate, boric acidiborate, tris(hydroxymethyl)aminomethane hydrohalide salt or carbonate.

14. The method of claim 11 wherein the pH of the aqueous solution is maintained in the range of about 7 to about 10.

15. The method of claim 11 wherein the metal seed layer comprises copper or copper alloys.

16. The method of claim 11 wherein the voltage is in the range of 0.2 to 5 volts.

17. The method of claim 11 wherein the voltage is in the range of 1 to 5 volts.

18. The method of claim 11 wherein the voltage is applied to the metal seed layer for 5 to 300 seconds.

19. The method of claim 11 wherein the electroplating bath comprises a source of copper ions, an electrolyte and optionally one or more accelerators, suppressors or levelers.

20. The method of claim 11 wherein a potentiostat is used to monitor the reduction of the oxidized metal.

21. A method for manufacturing an electronic device comprising the step of monitoring the oxidation state of metal in a seed layer deposited on a substrate.

23. The method of claim 21 wherein the electronic device is an integrated circuit.

24. The method of claim 21 wherein the substrate is a barrier layer.

22. The method of claim 22 wherein a potentiostat is used to monitor the oxidation state of the metal.