Abstract: A method for forming a crack which can precisely form a crack in a desired direction in substrates made of brittle materials even if the substrate of a large size is placed apart from a correct reference position on the scribe table. According to this method, a crack formation presumed line M is formed following the position separated from a beam travel line L, which is the track of the movement of the center of the beam spot B, by an offset amount O by moving a beam spot B relatively to a substrate G so that the beam travel line L can be in an oblique direction to a reference axis direction X set so as to be coincident with the substantial major axis direction of the beam spot B, and further a cooling spot C is relatively moved following the crack formation presumed line M, and thereby a vertical crack is formed following the crack formation presumed line M.

Abstract: A method for forming a crack which can precisely form a crack in a desired direction in substrates made of brittle materials even if the substrate of a large size is placed apart from a correct reference position on the scribe table. According to this method, a crack formation presumed line M is formed following the position separated from a beam travel line L, which is the track of the movement of the center of the beam spot B, by an offset amount O by moving a beam spot B relatively to a substrate G so that the beam travel line L can be in an oblique direction to a reference axis direction X set so as to be coincident with the substantial major axis direction of the beam spot B, and further a cooling spot C is relatively moved following the crack formation presumed line M, and thereby a vertical crack is formed following the crack formation presumed line M.