Oxygen-induced corrosion of copper plating substrates in acid sulphate electrolytes

M. Breathnach, S. Ahmed, R. Sharna, L. D. Burke, D. N. Buckley

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The corrosion of thin films of copper due to the presence of oxygen in CuSO4ZH2SO4 electrolytes was investigated. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images showed noticeable corrosion in aerated 0.1 mol dm-3 H 2SO4 electrolytes after times as short as 4 min while no significant corrosion occurred in de-aerated electrolyte. Etching was most evident at the grain boundaries but intra-granular etching was also noticeable. In CuSO4ZH2SO4, corrosion was slower at higher concentrations of CuSO4. A corrosion rate equivalent to 26 μA cm-2 was estimated by monitoring the concentration of copper in the 0.1 mol dm-3 H2SO4 electrolyte using atomic absorption spectrometry (AAS). Galvanostatic corrosion at 26 μA cm -2 showed somewhat different morphology. An oxygen reduction current of ∼0.8 μA cm-2 was measured in aerated 0.1 mol dm -3 H2SO4. The measured rate of corrosion of copper due to oxygen is thus ∼30 times that expected from the oxygen reduction current. The mechanism responsible for this enhanced oxygen reaction rate has not been determined. It is concluded that holding the potential at the equilibrium CuZCu2+ value in experiments such as in-situ AFM is not a practical solution to the problem of copper substrate corrosion.

Original languageEnglish
Title of host publicationECS Trancsactions - Electrochemical Processing in ULSI and MEMS 3
Pages51-63
Number of pages13
Edition8
DOIs
Publication statusPublished - 2007
EventElectrochemical Processing in ULSI and MEMS 3 - 211th ECS Meeting - Chicago, IL, United States
Duration: 8 May 20079 May 2007

Publication series

NameECS Transactions
Number8
Volume6
ISSN (Print)1938-5862
ISSN (Electronic)1938-6737

Conference

ConferenceElectrochemical Processing in ULSI and MEMS 3 - 211th ECS Meeting
Country/TerritoryUnited States
CityChicago, IL
Period8/05/079/05/07

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