Kinetic investigation of copper film oxidation by spectroscopic ellipsometry and reflectometry

This article presents the oxidation kinetics of Cu thin films in dry and we t oxygen at temperatures from 100 to 600 degrees C. Spectroscopic ellipsome try and reflectometry, which yield refractive index and thickness of the Cu oxide, were used in kinetic study of Cu film oxidation. Cabrera-Mott (C-M) theory was used for the calculation of oxidation activation energies, yiel ding 0.68 eV for dry oxidation and 0.43 eV for wet oxidation. The scanning electron microscopy (SEM) and Rutherford backscattering spectrometry were u sed to investigate the cross-sectional profile, grain size, and chemical co mposition of the Cu oxides. A formula for Cu oxide thickness calculation wa s derived from the C-M theory and experimental data: Good agreement has bee n observed in thickness values from formula calculation, spectroscopic refl ectance and SEM has been confirmed. A study of the effect of trace O-2 on C u film anneal is also presented. (C) 2000 American Vacuum Society. .[S0734- 2101(00)05705-5].