CHEMICAL VAPOR DEPOSITION OF COPPER FOR MICROELECTRONIC DEVICES BASED ON SILICON

Abstract
In this paper we present a study of copper CVD deposition on different types of substrates used for microelectronic devices. The influence of substrate temperature, pressure, flux and contamination effect of the gas phase has been determined to obtain the deposition conditions of the metallic films on substrate as clean Si and CrN. Copper acetylacetonate has been used as precursor. The CVD reactor is coupled to an ultra high vacuum chamber with Auger electrons spectroscopy which allows in situ surface characterizations. The chemical composition of the film has been measured for different deposition conditions. These surface techniques have been used with X-ray diffraction to characterize the deposited layers. In the case of silicon substrate the deposited film can either be a pure metal or a metal rich silicide near Cu₄Si at low or high substrate temperatures respectively. The formation of the copper silicide is compared to the case of Si/Cu junctions where the Cu layer is deposited by electron gun evaporation. Selectivity phenomena have also been observed : Cu growth rate is higher on metallic CrN substrate than on PPQ insulator.