METHOD AND DEVICE FOR SEPARATING A SUBSTRATE

摘要

The invention relates to a method and device for separating a substrate (2) by means of a laser beam (3). The duration of the effect of the laser beam (3) is extremely short such that the substrate (2) is only modified concentrically about the laser beam axis (Z) without it degrading the substrate material. Whilst the laser beam (3) acts upon the substrate (2), said substrate (2) moves relative to a laser machining head (10) such that a plurality of filament-type modifications are produced along a separating surface (5) which is to be incorporated. Said laser beam (3) is initially diverted by a transmission medium (8) having a higher intensity-dependent refractive index than air, and subsequently reaches the substrate (2). As the intensity of the used pulsed laser is not constant but increases to a maximum over the temporal course of the single pulse, and then reduces, the refractive index also changes. The focus point (9a) of the laser beam (3) moves between the outer surfaces (11, 12) of the substrate (2) along the beam axis (Z) such that it reaches the desired modification along the beam axis (Z) without correcting the laser machining head (10) in the z-axis.