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1989
Conference Paper
Titel
Selective tungsten metallization for 0.5 mym MOS processes
Abstract
Up to now conventional aluminum sputtering is a standard method for metallization in VLSI processes. With decreasing contact hole sizes down to the 0.5 mym range and aspect ratios bigger than 1, sputtering becomes more and more critical due to step coverage and reliability problems. A promising technique for future metallization processes is the contact hole filling by selective tungsten deposition. This metallization method was examined in a partially scaled 0.5 mym NMOS and PMOS process. Different contact schemes Si/TiSi2/W/Al, Si/W/Al and Si/Al were compared with regard to leakage current and contact resistance measurements, performed on diodes and Kelvin structures, respectively. Resistivity values 2 x 10 high minus 7 - 5 x 10 high minus 8 Omega square centimeter were evaluated for Si/TiSi2/W/Al contact systems. Contact hole structures, designed for scanning electron microscopy (SEM) analysis with dimensions down to 0.5 mym have been filled by selective W deposition.