METHOD FOR FORMATION OF VERTICAL CRACK IN BRITTLE MATERIAL SUBSTRATE AND METHOD FOR SEGMENTATION OF BRITTLE MATERIAL SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide a method which can form a vertical crack in a brittle material substrate with high reliability.SOLUTION: A method for formation of a vertical crack in a brittle material substrate comprises: a trench line formation process in which a trench line which is a line-shaped groove part is formed on one principal plane; an assist line formation process in which an assist line crossing the trench line is formed by pressure-welding rolling a scribing wheel which includes, on an outer peripheral part thereof, a tip provided with plural grooves at equal intervals. In the trench line formation process, a trench line is so formed that a crackless state is maintained just thereunder, and in the assist line formation process, an assist line is formed by use of a scribing wheel on which plural grooves are formed in an asymmetrical shape with respect to an outer periphery, and thereby extension of a vertical crack from a trench line is generated with an intersection point of both lines as an initiation point.SELECTED DRAWING: Figure 2