TGV drilling by Ultrafast Laser with Hollow Beam Optics

The TGV technology has attracted many attentions in IC packaging using glass as substrates due to its superior properties at for high density. Glass also gives advantages for developing cost effective solutions. Two optical properties, i.e. high band gap and transparency within visible and IR range cause the difficulty in applying laser to drilling of glass substrate. However, through the non-linear absorption incurred by ultrafast laser the micro size vias in glass material can be fabricated. In this study, we demonstrated combining non-diffraction Bessel optics and pico-second laser to fabricated high aspect ratio TGV in a few tens of micrometer diameter.