Removal of submicron particles from nickel-phosphorus surfaces by pulsed laser irradiation

Pulsed laser cleaning was demonstrated to be an efficient way for removing submicron particles from the nickel-phosphorus (NIP) surface both experimentally and theoretically. Experimentally, it is found that using KrF excimer laser with a pulse width of 23 ns the cleaning threshold is about 20 rrd/cm z for removing quartz particles from the NiP surface and laser cleaning efficiency increases rapidly with increasing laser fluence. The theoretical analysis shows that the peak cleaning force (per unit area) is larger than the adhesion force (per unit area) for submicron quartz particles on the NiP surface when it is irradiated by excimer laser with a fluence above 10 mJ/cm e. Therefore, it is possible to remove submicron quartz particles from NiP surfaces by laser irradiation. The difference between the cleaning force (per unit area) and the adhesion force (per unit area) increases with increasing laser fluence, leading to a higher cleaning efficiency for quartz particles on the NiP surface. © 1997 Elsevier Science B.V.