Dry cleaning for metallic contaminants removal as the second cleaning process after the CMP process

In this study the removal of the metallic contaminants like Cu, K, and Fe commonly found on the wafer surface after scrubbing which is widely used as a post-chemical mechanical polishing(CMP) cleaning technique are investigated by remote hydrogen plasma and UV/O3 cleaning techniques. Our results show that metal contaminants including Cu, K, and Fe can be effectively removed by a hydrogen plasma or UV/O3 cleaning technique, if it is performed under optimum process conditions. In the remote plasma H2 cleaning contaminants removal is enhanced with decreasing the plasma exposure time and increasing the rf-power. The optimum process conditions for the removal of Cu, K, and Fe impurities existing on the wafer surface are the plasma exposure time of 1 min and the rf-power of 100 W. The surface roughness decreased by 30–50% after the 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.