Surface smoothing of copper by electropolishing

Patent metadata

Field	Value
Publication number	US-11447887-B2
Application number	US-202017118115-A
Country	US
Kind code	B2
Filing date	Dec 10, 2020
Priority date	Dec 10, 2020
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

A method for forming an atomically smooth surface on a copper electrode through electropolishing and the atomically smooth surface are provided. An exemplary method for forming an atomically smooth surface by electropolishing includes placing a copper foil in an electrolyte solution including ethylene glycol and phosphoric acid. The copper foil is coupled to a current source. Current is applied to the copper foil to electropolish the copper foil. The electropolishing is stopped when the electropolishing is completed.

First claim

What is claimed is:

1. A method for forming an atomically smooth surface by electropolishing, comprising:
placing a copper foil in an electrolyte solution consisting of about 0.2 molar (M) ethylene glycol and about 3 M phosphoric acid;
coupling the copper foil to a current source;
applying current to the copper foil to electropolish the copper foil; and
stopping the electropolishing when the electropolishing is completed, wherein the electropolished copper foil has a surface roughness of about 3 nm.

2. The method of claim 1 , comprising forming the electrolyte solution by mixing an 85% phosphoric acid solution into water and then adding the ethylene glycol to the electrolyte solution.

3. The method of claim 1 , comprising applying the current at about 380 mA per 2 cm 2 to the copper foil.

4. The method of claim 1 , comprising determining that the electropolishing is completed when the electrolyte solution changes color to blue.

5. The method of claim 1 , comprising determining that the electropolishing is completed after about 11.5 minutes.

6. The method of claim 1 , comprising using a counter electrode comprising a second copper foil.

7. The method of claim 1 , comprising controlling a temperature during the electropolishing at about 65° C.

8. The method of claim 1 , comprising using the copper foil as a working electrode in an electrochemical cell.

9. The method of claim 1 , comprising coupling two copper foils to the current source as working electrodes.

10. The method of claim 1 , comprising using a sense lead to monitor the current of a working electrode.

11. The method of claim 1 , comprising using a Ag/AgCl electrode as a reference electrode.

Assignees

• Saudi Arabian Oil Co
• Univ King Fahd Pet & Minerals

Inventors

• Al-Rowaili Fayez Nasir
• Khaled Mazen
• Jamal Aqil
• Onaizi Sagheer A
• Zahid Umer

Classifications

• C25B11/042

  Electrodes formed of a single material · CPC title

• C25D5/34

  Pretreatment of metallic surfaces to be electroplated · CPC title

• C25B11/061

  Metal or alloy · CPC title

• C25F3/22 Primary

  of heavy metals · CPC title

• C25D11/34

  of metals or alloys not provided for in groups C25D11/04 - C25D11/32 · CPC title