Post-CMP cleaning for metallic contaminants removal

초록

Results and Discussion Our results show that metal contaminants including Cu, K, and Fe can be effectively removed by a hydrogen plasma or UV/O3 cleaning technique, of it is perforned under optimum process conditions. In the remote plasma H2 cleaning contaminants removal is enhanced with decreasing the placma exposure time and increasing the rf-power. The optimum process conditions for the removal of Cu, K, and Fe impurities existing on the wager surface are the plasma exposure time of 1 min and the rf-power of 100 W. The surface roughness decreased by 30-50% after remote plasma H2 cleaning. On the other hand. the highest efficiency of Cu, K and Fe impurities removal was achieved for the UV exposure time of 30 s. The removal mechanism of the metallic contaminants like Cu, K and Fe in the remote plasma H2 and the UV/O3 cleaning processes is as follows: the metal atoms are lifted off when the SiO is removed by evaporation after the chemical or native SiO2 formed underneath the metal atoms react with H+ and e- to form SiO.