Product Code: ICAL07_M102

Via Hole Machining in Sapphire using an Ultrafast Laser
Authors:
Nagaraj Batta, Panasonic Boston Lab; Cambridge MA USA
Shuichi Nagai, Panasonic Boston Lab; Cambridge MA USA
Ming Li, Panasonic Boston Lab; Cambridge MA USA
Presented at ICALEO 2007

GaN is expected to replace GaAs and Si materials in the next generation high power density Microwave Monolithic Integrated Circuits (MMIC), thanks to its excellent material characteristics. Sapphire is one of the most promising substrate materials for GaN-based MMIC for its excellent physical characteristics and cost effectiveness. Interconnects across MMIC devices are made possible by via holes through sapphire layer, which is typically > 100 um in depth. Since sapphire is chemically stable and physically strong, it is very difficult to make such deep via holes in sapphire using conventional techniques, such as wet or dry etching. Our picosecond laser provides a viable, and probably unique, solution to this problem. It was demonstrated that > 300 um holes can be machined in sapphire with our 526 nm picosecond laser.