IMPROVED PHOSPHOSILICATE GLASS PASSIVATION AGAINST CU CONTAMINATION USING THE RAPID THERMAL ANNEALING PROCESS

Passivation against Cu contamination is a key technology for realizing multilevel Cu interconnection for ultralarge scale integrated circuit s (ULSI). Phosphosilicate glass (PSG) with rapid thermal annealing (RT A) is found to provide no less of a passivation effect than furnace-an nealed (FA) PSG films, while significantly reducing the thermal budget of the PSG annealing from 900-degrees-C x 20 min (FA) to 900-degrees- C X 60 s (RTA). This suggests that the PSG-RTA process is applicable t o 0.25 mum level metal oxide semiconductor (MOS) ULSIs, since both the amount of Cu diffusion and the thermal budget are within the limits o f 0.25 mum MOS device technology.