Product Code: ICAL09_M304

Debris-free Low-stress Laser Dicing for Multi-layered MEMS Wafer
Authors:
Masayuki Fujita, Institute for Laser Technology; Osaka Japan
Yusaku Izawa, Institute of Laser Engineering, Osaka University; Suita Japan
Yosuke Tsurumi, Institute of Laser Engineering, Osaka University; Suita Japan
Shuji Tanaka, Tohoku University; Sendai Japan
Hideyuki Fukushi, Tohoku University; Sendai Japan
Keiichi Sueda, Institute of Laser Engineering, Osaka University; Suita Japan
Yoshiki Nakata, Institute of Laser Engineering, Osaka University; Suita Japan
Noriaki Miyanaga, Institute of Laser Engineering, Osaka University; Suita Japan
Masayoshi Esashi, Tohoku University; Sendai Japan
Presented at ICALEO 2009

We have developed a novel debris-free low-stress in-air laser dicing technology for multi-layered MEMS wafers, which are generally consisted of glass and silicone. Our technology combines two processes: dicing guide fabrication and wafer separation process. The first process is the internal transformation using a pulsed 1micron laser. The second process is non-contact separation by thermally-induced crack propagation using a CO2 laser or mechanical separation by bending stress. We tested several pulsed lasers with different pulsewidths, including a Nd:YVO4 laser and an Yb fiber laser for generating the internal transformation in silicon and/or glass. The internal transformed lines worked well as a guide of the separation. We found that the internal transformation only in silicone layer was enough for dicing the glass/silicone double-layered wafer. Also the thermal stress induced by the CO2 laser was quite effective to propagate the crack inside the glass layer without internal transformation. The double-layered wafer consisting of glass and silicon can be diced in low stress by our technology.