Si wafer surface cleaning using laser-induced shock wave: a new dry cleaning methodology

It was investigated that a new dry cleaning methodology named laser shock cleaning could be applied to remove the particles from the wafer surface. The γ-alumina particles of 0.05 μm in diameter were deposited uniformly on bare Si wafer surface by aerosol spray method. The number of particles on wafer surface was measured by surface scanner before and after cleaning. It was found that most of the particles on the wafer surface were removed after dry shock cleaning using Nd:YAG laser. The average removal efficiency of the particles was over 90%, and the larger particles are easier to remove from the surface due to their smaller adhesion force. The removal efficiency of particles increased slightly as the particle size was to be larger.