METHOD FOR REMOVING BRITTLE-HARD MATERIAL BY MEANS OF LASER RADIATION

摘要

Laser radiation is used for removing brittle-hard material from a substrate without damaging the material. A removal depression having a flank angle w of the flanks of the removal depression forms in the material as a result of the removal. The removal depression forms with an entry edge, which is defined as a spatially expanded region of the surface of the material, where an unchanged and thus unremoved portion of the surface of the material transitions into the removal depression. Spatial portions of the laser radiation are refracted and focused into the volume of the unremoved material at this entry edge. The distribution of the laser radiation is set such that the entry edge assumes a small spatial expansion, such that the portion of the power of the laser radiation, which is captured by the focusing effect of the entry edge, is not sufficient to generate a threshold value ρdamage for the electron density in the volume of the material, thus avoiding damage to the material.

主权项

1. In a method for removing brittle-hard material from a substrate by means of laser radiation, wherein a removal depression having a flank angle w of the flanks of the removal depression forms in the material as a result of the removal, wherein the flank angle w is defined as the angle between the surface normal on the flank of the removal depression and the surface normal on the unremoved surface of the material, and forms with an entry edge, which is defined as a spatially expanded region of the surface of the material, where an unchanged and thus unremoved portion of the surface of the material transitions into the removal depression, and at which spatial portions of the power of the laser radiation are refracted and focused into the volume of the unremoved material, the improvement comprising the step of setting the distribution of the laser radiation such that the entry edge assumes a spatial expansion such that said portion of the power of the laser radiation that is captured by the focusing effect of the entry edge is not sufficient to generate a threshold value ρdamage for the electron density in the volume of the material, thus avoiding damage to the material.