Experimental validation of model for pulsed-laser-induced subsurface modifications in Si

Wafers are traditionally diced with diamond saw blades. Saw dicing technology has a number of limitations, especially concerning the dicing of thin wafers. Moreover, the use of fluids and the gen-eration of debris can damage fragile components such as micro electro-mechanical systems. Laser ablation dicing is better suited for thin wafers, but is also not a clean process. An alternative dicing method is subsurface laser dicing. This technology is based on the production of laser-induced sub-surface modifications inside the wafer. These modifications weaken the material, such that the wafer separates along the planes with laser modifications when applying an external force. To find the right laser conditions to produce subsurface modifications in silicon, and to enhance the understand-ing of the underlying physics, a numerical model has previously been developed. To validate this model, the current work compares simulation results with experimental data obtained by focusing nano- and picosecond pulses inside silicon wafers. A fairly good agreement between experimental and numerical results was obtained