High-rate deposition of high-quality Cu film with LPCVD

Basic process characteristics for Cu film deposition to be used in advanced ULSI interconnects have been studied by thermal LPCVD with liquid precursor Cu(hfac)(tmvs) (hexafluoro-acetylacetonate trimethyl-vinylsilane copper). For sufficient productivity in practical use, efforts were concentrated into obtaining high deposition rate with high film qualities of specific resistivity, surface flatness and adhesion. Three process chambers for preheating, TiN-PVD, and Cu-CVD functions were mounted on an ANELVA I-1060 single wafer cluster tool machine, where 6 inch wafers could be processed. Relationships between the deposition rate, specific resistivity, and Cu-CVD process parameters were analyzed using RSM (response surface methodology). Deposition rate over 100 nm/min was obtained at wafer temperature of 200°C, precursor flow rate of 0.67 g/min, carrier N2 flow rate of 400 sccm, and purge Ar flow rate of 125 sccm with specific resistivity of about 1.8 μΩ cm on TiN underlayer. This shows a promising process for future Cu interconnect technology.