METHOD AND APPARATUS FOR LASER-MACHINING SILICON BY FILAMENTATION OF BURST ULTRAFAST LASER PULSE

摘要

PROBLEM TO BE SOLVED: To provide a laser-scribing method of silicon, which results in near-zero kerf widths and decreases in roughness.SOLUTION: A method of laser-machining silicon includes a step of placing a Kerr material such that the same engages with the silicon and forming an interface between the Kerr material and the silicon which is a transparent object substrate 10. A laser beam 2 is applied including in a burst envelope at least one subpulse operating at a first wavelength. The laser beam passes through a distributive lens focusing device 26 and reaches the Kerr material. The first wavelength is modified to a plurality of second wavelengths, and some of the second wavelengths are effective for the machining of silicon. Photoacoustic compression processing is produced by initiating Kerr effect self focusing with the laser pulse energy by a portion of the second wavelengths delivered through the interface to the silicon and by propagating the self focusing in the silicon by additional energy inputted to the silicon and thus producing a filament in the silicon.