Simulation of laser ablation mechanism of silicon nitride by ultrashort pulse laser

摘要

A mathematical model is developed to find the depth of laser ablation and laser-material interaction in laser processing of Si_3N_4 (SL200-BG) by an ultrashort (picosecond) pulse laser. The model is verified with experiments which were carried out at different laser scan speeds from 1 mm/s to 100 mm/s. Experimental validation shows a model accuracy of 85%. Additionally, the results show that in laser intensities (I_L) higher than 1.5 × 10~9 W/cm~2, the laser-material interaction is "Multi Photon Ionization" (MPI) with no effects of thermal reaction while in lower values of I_L, there are effects of thermal damages adjacent to the laser cut.