Patent ID: 8969752
Filing Date: 2015-03-03
Classification: B23K,B28D,Y10S,Y10T

Abstract:
1. A laser processing method for cutting a flat object to be processed including a substrate and a laminate part disposed on the substrate, the method comprising the steps of: attaching a protective film to a front face of the object on the laminate part side; irradiating a portion of a rear face of the object with laser light, after the step of attaching the protective film, wherein the portion of the rear face of the object comprises a laser light entrance surface, and converging the laser light at a light-converging point within the substrate to form a modified region along a cutting line, wherein the modified region is a cutting start region located in the object by a predetermined distance from the rear face such that a fracture is naturally grown in a thickness direction of the object after the forming of the cutting start region in the substrate, and the fracture reaches both the front face and the rear face of the object thereby dividing the object into a plurality of parts without separating adjacent parts of the plurality of parts from each other; attaching an expandable film to the rear face of the object, after the step of irradiating the object; and separating the adjacent parts of the plurality of parts from each other by expanding the expandable film so that a gap exists between the adjacent parts of the plurality of parts, after the step of attaching the expandable film.