Effect of Cu-Ion concentration in concentrated H3 PO4 electrolyte on Cu electrochemical mechanical planarization

Te Ming Kung, Chuan Pu Liu, Shih Chieh Chang, Kei Wei Chen, Ying Lang Wang

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8 Citations (Scopus)


The influence of Cu-ion concentration in a concentrated H3 PO4 electrolyte on the Cu removal rate and planarization efficiency (PE) of electrochemical mechanical planarization (ECMP) was investigated. With increasing Cu-ion concentration in the electrolyte, results show that the Cu removal rate significantly decreased because more Cu ions in the electrolyte facilitated the formation of a surface passive film. Electrochemical analysis shows that the current density decreased from 91 to 62 mA/ cm2 when the Cu-ion concentration was increased from 35.8 to 158.6 mM. In a low Cu-ion concentration electrolyte, Cu (OH)2 is dominant, while in a high Cu-ion concentration electrolyte, CuO predominates. A high Cu-ion concentration in the electrolyte during ECMP promotes the formation of CuO, which retards Cu-ion diffusion from the Cu surface to the electrolyte solution, resulting in a decrease in the Cu removal rate. The intensity ratio of CuO/ [Cu (OH) 2 +CuO] in the Cu 2p3/2 X-ray photoelectron spectroscopy spectrum increased from 22.1 to 85.6% when the Cu-ion concentration was increased. The effect of Cu-ion concentration on the microscale PE of Cu ECMP is discussed.

Original languageEnglish
Pages (from-to)H763-H770
JournalJournal of the Electrochemical Society
Issue number7
Publication statusPublished - 2010 Jun 10

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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