Cleaning of CHF3 plasma-etched SiO2/SiN/Cu via structures with dilute hydrofluoric acid solutions

Kazuyoshi Ueno, Vincent M. Donnelly, Takamaro Kikkawa

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37 Citations (Scopus)


After etching in a CHF3/Ar electron cyclotron resonance plasma, SiO2/SiN/Cu via structures for multilevel Cu interconnection were investigated with angle-resolved x-ray photoelectron spectroscopy. Photoelectron shadowing, determined by x-ray photoelectron spectroscopy takeoff angle, and electrostatic charging were used to determine the chemical composition and amount of contamination on the dielectric horizontal surfaces and via sidewalls, as well as on the Cu at the bottoms of the via holes. All surfaces were covered with one to two monolayers of a CFx layer (CF > CF2 > CF3). The dielectric surfaces were also covered with a small amount (∼0.1 monolayers) of Cu, and the Cu at the bottom of the via was contaminated with O (mainly CuO) and F. After cleaning with dilute HF solution, the dielectric surfaces were free of Cu and most of the F and C. CuO was also removed from the Cu surface by this treatment; however, Cu2O and CFx remained.

Original languageEnglish
Pages (from-to)2565-2572
Number of pages8
JournalJournal of the Electrochemical Society
Issue number7
Publication statusPublished - 1997 Jul
Externally publishedYes

ASJC Scopus subject areas

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


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