METHOD AND DEVICE FOR SEPARATING A SUBSTRATE

摘要

A method and device for separating a substrate with a laser beam. The duration of the laser beam's effect is extremely short, so the substrate is only modified concentrically about the laser beam axis (Z) without it degrading the substrate material. While the laser beam acts upon the substrate, the substrate moves relative to a laser machining head, producing plural filament-type modifications along a separating surface to be incorporated. The laser beam is initially diverted by a transmission medium having a higher intensity dependent refractive index than air, then reaches the substrate. The non-constant pulsed laser intensity increases to a maximum over the temporal course of the single pulse, then reduces, and the refractive index changes. The laser beam focus point moves between the substrate's outer surfaces along the beam axis (Z), reaching the desired modification along the beam axis (Z) without correcting the laser machining head in the z-axis.

主权项

1. A method for separating a substrate using an optical system, a thickness of the substrate not exceeding 2 mm in a region of a separating line, the method comprising:
applying pulsed laser radiation having a pulse duration (t) to a substrate material of the substrate, which material is transparent at least in part to a laser wavelength, the laser radiation being focused using the optical system having an original focal depth (f1), an intensity of the laser radiation leading to a modification of the substrate along a beam axis (Z) of the laser radiation, but not to material removal which goes all the way through, and the pulsed laser radiation being moved along any desired separating line parallel to the primary extension plane of the substrate, bringing about a subsequent separation process along the separating line, wherein the pulsed laser radiation is focused by the same optical system, which is unchanged per se, at a focal depth (f2) different from the original focal depth (f1), by non-linear self-focusing within the pulse duration (t) of an individual pulse (P).