Microstructure and formation of copper oxide in the Cu electro-polishing process

Te Ming Kung, Michael Rong Shie Huang, Jung Chih Tsao, Chuan Pu Liu, Ying Lang Wang

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


In this study, the formation of Cu oxide on Cu film is studied during Cu electropolishing in a phosphoric acid-based electrolyte with various Cu ion concentrations, from 2.28% to 10.08%. In cyclic voltammetry measurement, the maximum current density of the anodic peak (l max) decreases from 38.87 to 28.13 mA/cm 2 with increasing Cu ion concentration, indicating that an oxide film forms on the Cu film surface and the thickness increases with Cu ion concentration. Microstructures and crystallography of the oxide film are examined by transmission electron microscopy, which confirms the increase of the oxide film thickness due to the high Cu ion concentration in a H 3PO 4 electrolyte. Three types of Cu oxide are detected using X-ray photoelectron spectroscopy, namely Cu 2O, Cu(OH) 2, and CuO. With a Cu-ion electrolyte concentration of less than 6.99%, Cu(OH) 2 is dominant, while at higher Cu-ion concentrations, CuO predominates. The formation of CuO protects Cu from corrosion in the electrolyte with the Cu-ion concentration of over 6.99%.

Original languageEnglish
Pages (from-to)7065-7069
Number of pages5
JournalJournal of Nanoscience and Nanotechnology
Issue number11
Publication statusPublished - 2010 Nov 1

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics


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