Laser shock cleaning of inorganic micro and nanoscale particles

A new dry cleaning technology; laser-induced shock cleaning has been applied to remove the submicron particles (including post-CMP (chemical-mechanical polishing) slurries from silicon wafer surfaces. The cleaning effectiveness of the new technology was evaluated quantitatively using a laser surface scanner. The results show that most of the silica particles on the wafer surface were removed after exposure to the laser-induced shock waves. The average removal efficiency of the particles was over 99%. The results show that cleaning efficiency is strongly dependent on a gap distance between laser focus point and the wafer surface and that a suitable control of the gap is crucial for the successful removal of the particles. In addition, this new technique was also applied successfully to the removal the post-CMP slurries from a polished patterned wafers.