Patent ID: 7726532
Filing Date: 2010-06-01
Classification: B23K,B28D,C03B,Y10T

Abstract:
1. A method of forming a crack in substrates made of brittle materials, comprising the steps of irradiating a laser beam which can form a beam spot substantially having the major axis to a substrate, forming a cooling spot by emitting a jet of refrigerant to the substrate, and locally causing thermal stress to the substrate by heating with the irradiation of the laser beam and cooling with the emission of a jet of refrigerant, wherein the beam spot is moved relatively to said substrate in such a way that the direction of a beam travel line, which is the track of the movement of the major axis center of the beam spot, can be in an oblique direction to the reference axis direction set to be coincident with the major axis direction of the beam spot, the cooling spot is relatively moved following a crack formation presumed line in a position separated from the beam travel line by an offset amount.