LASER CLEANING OF MICROPARTICLES FROM A SOLID-SURFACE - THEORY AND APPLICATIONS

In laser cleaning of micro-particles from a solid surface, the adhesio n force between the particles and the substrate surface, and the therm al expansion of both particles and substrate play important roles in d etermining the threshold laser fluence. Taking into account Van der Wa als force and cleaning force due to fast thermal expansion of particle s and substrate surface induced by pulsed laser irradiation, a cleanin g model was established for the removal of tiny particles from substra te surfaces. The cleaning condition and cleaning threshold can be obta ined from this model. This model can qualitatively and quantitatively predict the laser cleaning process depending on laser incident directi on, laser wavelength, particle size, particle material and substrate m aterial. (C) 1998 Elsevier Science S.A. All rights reserved.