EFFECTS OF REACTION-KINETICS ON THE MICROSTRUCTURE OF CHEMICAL-VAPOR-DEPOSITED COPPER-FILMS - EXPERIMENT AND SIMULATION

The microstructure of chemical vapour deposited copper films was studi ed using two different metalorganic precursors, namely bis(dipivaloylm ethanato) Cu(II) or Cu(dpm)(2) and bis(t-butylacetoacetato) Cu(II) or Cu(tbaoac)(2). The microstructure of copper films deposited from Cu(dp m)(2) showed a strong dependence on growth temperature. Films deposite d from Cu(dpm)(2) at 350 degrees C are dense and well-connected. Incre ased growth temperature, however, yields larger grain size and higher degree of void incorporation into the films, resulting in higher elect rical resistivity. Films grown at 450 degrees C consist of well-separa ted and faceted grains. In contrast, growth rates of copper films grow n from Cu(tbaoac)(2) were significantly lower (2 nm/min at 320 degrees C for Cu(tbaoac)(2) as against 17 nm/min at 380 degrees C for Cu(dpm) (2)). Also, pyrolysis of Cu(tbaoac)(2) yielded Cu films with remarkabl y fine grain structure. In an attempt to understand the roles of chemi cal kinetics and the different atomic level processes involved in micr ostructural changes in copper films grown by chemical vapour depositio n (CVD), a Monte Carlo simulation has been employed. Our simulation re sults confirm that chemical kinetics, along with surface and interface mobility of the growth species, play a pivotal role in determining th e microstructure of copper films. (C) 1997 Elsevier Science S.A.