Open AccessVery large spot size effect in nanosecond laser drilling efficiency of silicon
Author(s) -
F. Brandi,
Nicolas Burdet,
Riccardo Carzino,
Alberto Diaspro
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.023488
Subject(s) - materials science , fluence , nanosecond , optics , laser , excimer laser , silicon , laser drilling , ablation , wafer , laser ablation , excimer , laser beam machining , x ray laser , optoelectronics , laser power scaling , laser beams , physics , engineering , aerospace engineering
The effect of the spot diameter in nanosecond excimer laser percussion drilling of through via in silicon wafer is presented. Experimental results show a ten fold increase of the ablation efficiency when decreasing the spot diameter from 220 μm to 9 μm at constant fluence in the range 7.5 J/cm(2) to 13.2 J/cm(2). Such effect is absent when using 60 ps deep-UV laser pulses. A model is developed that explain the findings in terms of plume shielding effect on the laser pulse. The model is successfully applied also on previously published data on deep-UV laser drilling of Polyamide and Alumina.