Micro-machinability of silver–sodium ion-exchanged glass by UV nanosecond laser

Micro-machining of silver–sodium ion-exchanged lime-sodium glass was carried out using fourth harmonic generation (FHG) of Nd:YAG nanosecond laser. The laser irradiations to silver-doped glasses produced low aspect ratio and defect-free holes because of their high-optical absorptions at the vicinity of ion-exchanged surfaces. The ablation rates (i.e. removed depth per laser shot) of ion-exchanged glasses gradually decreased with the distance from glass surfaces and were saturated, corresponding to the dilution of silver ion concentration. The ablation rates and hole shapes drastically changed when the processed hole bottoms reached the ion penetration depths. Scanning electron microscope images indicated that the walls of processed holes in non-silver-containing region had irregular-shaped and porous structures. Therefore, well-designed ion distributions were necessary for the high-accuracy fabrication of micro-components. From these results, a micro-channel and a cylindrical column-shaped cantilever were fabricated on the glass substrates.