Debris-free high-speed laser-assisted low-stress dicing for multi-layered MEMS

We have investigated a novel debris-free high speed laser dicing technology for MEMS. The target were a Tempax or Pyrex glass and silicon and their anodically-bonded multi-layered wafers. Our technology combines three processes: dicing guide fabrication, wafer separation process, and a tape expansion. First process was the internal transformation using a nanosecond Nd:YVO ₄ laser. The laser pulse width and repetition rate was 11 ns and 20 - 100 kHz. The laser scanning speed was over 100 mm/sec. The second process was a mechanical bending separation. The bending stress for glass and Si wafer separation was 10 and 100 MPa, respectively. At the third step, spaces between chips were opened by the tape expansion. The internal transformation fabricated in the first process worked well as the guide of the separation. The diced lines completely followed the internal transformation.