We have developed a novel debris-free in-air laser dicing technology, which gives more design freedoms in the structure, process and materials of MEMS as well as improves yields. Our technology combines two processes: dicing guide fabrication and wafer separation process. The first process is the internal transformation using a fundamental wavelength of a Ti:Sapphire laser or a Nd:YAG laser. The second process is non-contact separation by thermally-induced crack propagation using a CO2 laser or mechanical separation by bending stress. The internal transformation fabricated in the first process worked well as the guide of separation, and the processed wafer was diced with low stress. The diced lines completely followed the internal transformation.