Highly conformal Cu thin films were deposited on the SiO2 trench substrate with an aspect ratio of 10 by pulsed metallorganic chemical vapor deposition (MOCVD) using cycles of the alternate supply of (hexafluoroacetylacetonate) Cu-(I)(3,3-dimethyl-1-butene) [(hfac) Cu(DMB)] pulse and argon purge gas. The film was 75 nm thick with a good step coverage. The growth temperature was 70 degreesC and the growth rate was 0.75 - 1.1 Angstrom/ cycle depending on the (hfac) Cu(DMB) pulse duration of 5 - 10 s. X-ray diffraction patterns of the Cu films showed a preferential crystallographic orientation of (111) plane of Cu. The impurities of C and F atom in the Cu films were below detection limits and only O atom was detected lower than 3 average atom % by X-ray photoelectron spectroscopy. (C) 2003 The Electrochemical Society.