The dependence of the microstructure on the electrical property of copper thin films prepared by metal organic chemical vapor deposition has been studied. The copper films have been deposited onto TiN substrates by varying the substrate temperature and carrier gas flow rate with a precursor of hexafluoroacetylacetonate trimethylvinylsilane copper(I). The film microstructures have been analysed by transmission electron microscopy (TEM) and Auger electron spectroscopy (AES), and the film resistivity has been measured by a four-point probe. Results of the measurement indicate that the resistivity is strongly dependent of the substrate temperature during the film deposition. The electrical resistivity of the films slightly increase above 180 degrees C, due to the presence of the carbon content of the films. Post-annealing of the films after copper deposition below 180 degrees C has effectively reduced the film resistivity.