Removing nanoparticles from substrate is a challenging task with numerous critical applications. Laser shockwave cleaning technique, which is dry and non-contact, takes advantages of shockwave fronts initiated by plasma formation under a focused laser beam.
In the reported experiments, a Q-switched Nd:YAG pulsed laser with 1064 nm wavelength is employed as a shockwave generation source. Images before and after cleaning of silicon wafer are measured by optical microscope.
Experimental results indicate that PSL particles with 1 μm, 500nm, 200nm diameters on silicon wafers can be removed without substrate damage. The influence of mixed different size particle, substrate roughness and double shockwave on the cleaning efficiency is reported.
The laser cleaning experiments of wafers, on which different size particles exist together, show that it is possible to remove bigger particles without the influence on smaller particles.
The laser cleaning efficiency from rough substrate is lower than that from the smooth substrate at same laser incident energy. But the laser cleaning efficiency from rougher substrate is also promoted to the same efficiency in case of smooth substrate as laser energy increases.
It is founded that cleaning by double shockwave provides an advantage in speed for cleaning large areas.
