Product Code: ICAL06_M105

Analysis of Modified Layer Formation into Silicon Wafer by Permeable Nanosecond Laser
Authors:
Etsuji Ohmura, Osaka University; Suita, Osaka Japan
Kenshi Fukumitsu, Hamamatsu Photonics K.K.; Iwata Japan
Naoki Uchiyama, Hamamatsu Photonics K.K.; Iwata Japan
Hideki Morita, Hamamatsu Photonics K.K.; Iwata Japan
Kazuhiro Atsumi, Hamamatsu Photonics K.K.; Iwata Japan
Masayoshi Kumagai, Hamamatsu Photonics K.K.; Iwata Japan
Presented at ICALEO 2006

When a permeable pulse laser which is focused into the inside of a silicon wafer is scanned in the horizontal direction, a belt-shaped high dislocation density layer including partially polycrystalline region is formed in the wafer. When tensile stress is applied perpendicularly to this belt-shaped modified-layer, silicon wafer can be divided easily, because the cracks that spread from the modified layer up and down progress to the surface. This technology is called "stealth dicing" (SD), and attracts attentions as novel dicing technology in semiconductor industries. In this study, formation mechanism of the modified layer was explained by the heat transfer analysis in which the temperature dependence of absorption coefficient is considered and thermal stress analysis based on those results. It was supported by the present analysis that the problem of thermal effect to the active region can be solved by the SD method.