PROCESS OPTIMIZATION OF COPPER MOCVD USING MODELING EXPERIMENTAL-DESIGN

An optimisation of copper CVD was carried out through the use of scree ning and modeling experimental designs. The copper precursor [Cu(hfac) tmvs] was delivered through a bubbler using hydrogen as carrier gas. W ater vapour was used as reactant. Films were deposited on sputtered ti tanium nitride substrate. The influence of substrate temperature, carr ier gas flow, water flow, water injection time and bubbler pressure we re studied and led to experimental laws, which show the dependence of resistivity and deposition rate with any of these parameters. It was f ound that the optimum procedure was to inject water during a limited t ime at the beginning of the growth (typically 2 minutes, for an overal l deposition time of 30 minutes). This improves the nucleation but avo ids the oxidation of the film. Consequently, the resistivity is very l ow and the deposition rate is relatively high. For the optimum working point, in terms of resistivity (1.9 mu Omega . cm after anneal), X-ra y photoelectron spectroscopy (XPS) depth profiling indicates a pure co pper phase. The adhesion on the TiN substrate was excellent according to the ''Scotch tape'' test.