Post-CMP cleaning for metallic contaminant removal by using a remote plasma and UV/ozone

for the chemical mechanical polishing (CMP) process to be successful, it is important to establish a good post-CMP cleaning process that will remove n ot only slurry and particles but also metallic impurities from the polished surface. The common metallic contaminants found after oxide CMP and Cu CMP include Cu, K, and Fe. Scrubbing. a popular method for post-CMP cleaning, is effective in removing particles, but removal of metallic contaminants: u sing this: method is not so effective. In this study, the removal of Fe met allic contaminants like Fe, which are commonly found on the wafer surface a fter CMP processes, was investigated using remote-hydrogen-plasma and UV/O- 3 cleaning techniques. Our results show that metal contaminants. including Fe, can be effectively removed by using a hydrogen-plasma or UV/O-3 cleanin g technique performed under optimal process conditions. In remote plasma H- 2 cleaning, contaminant removal is enhanced with decreasing plasma exposure time and increasing rf-power. The optimal process condition for the remova l of the Fe impurities existing on the wafer surface is an rf-power of 100 W. Plasma cleaning for 5 min or less is effective in removing Fe contaminan ts, but a plasma exposure time of 1 min is more appropriate than 5 min in v iew of the process time. The surface roughness decreased by 30 similar to 5 0 % after remote-H-2-plasma cleaning. On the other hand, the highest effici ency of Fe-impurity removal was achieved for an UV exposure time of 30 s, T he removal mechanism for the Fe contaminants in the remote-H2-plasma and th e UV/O-3 cleaning processes is considered to be the liftoff of Fe atoms whe n the SiO* is removed by evaporation after the chemical or native SiO2 form ed underneath the metal atoms reacts with H+ and e(-) to form SiO*.