Patent ID: 7772522

Claim:
A scribing method for a brittle material substrate, wherein the brittle material substrate is continuously heated by a first laser spot to a temperature which is lower than a softening point of the brittle material substrate, along a scribe line formation line on a surface of the brittle material substrate, along which a scribe line is to be formed, while an area close to the first laser spot is continuously cooled along the scribe line formation line; and an area which is close to the cooled area and is on an opposite side to the first laser spot is continuously heated by a second laser spot along the scribe line formation line to a temperature which is lower than the softening point of the brittle material substrate, wherein both sides of the scribe line formation line at an edge portion of the brittle material substrate are preheated with separate preheating spots spaced apart from and on opposite sides of the scribe line immediately before being heated by the first laser spot.