Sapphire Surface Protection During Sapphire Micromachining and Through-Sapphire Via Formation for Device Densification, Backside Interconnect and Chip Stacking

摘要

Through-vias in sapphire can aid in silicon-on-sapphire device densification and chip stacking. They can also help connect with electronic structures made on the back of the sapphire. Through-vias in sapphire can be formed using an appropriate laser. During the formation of through-vias in sapphire using a laser and during laser micromachining of sapphire, debris and heat-affected zones were produced. Various methods were evaluated to protect the circuitry on the sapphire from damage by debris and heat produced during laser application. Results of the evaluations are outlined and an effective method to help remove debris and reduce the effect of heat is described.