Novel micro-welding of silicon and glass by ultrashort pulsed laser

The laser welding can provide flexible processing, and ultrashort pulsed laser with high pulse repetition rates enabled locally selective welding of monocrystalline silicon and glass with comparable processing performance to anodic bonding method. The 20ps laser pulse of 1060nm was absorbed at monocrystalline silicon through glass plate, and its surface temperature reached its boiling temperature. In addition, it was considered that the absorption of laser energy to glass was occurred, and the temperature of glass increased more than the forming temperature. Thus the convection of silicon and glass was caused by the recoil pressure of evaporation, which led to mild mixture of silicon and glass. This phenomenon produced anchor geometry at the interface between silicon and glass without gap generation. The number of laser shot in the laser spot had an influence on shearing strength of weld joint, and higher shearing strength of weld joint could be performed at proper number of laser shot in the laser spot.