METHOD OF MACHINING VULNERABLE MATERIAL SUBSTRATE

摘要

A method of machining a fragile material substrate enables stable laser break processing. The method of machining, in machining the substrate from a first substrate end to a second substrate end along a scribe-scheduled line, executes a step (a) of forming a first early crack so as to be separated from the first substrate end, a step (b) of heating the substrate while relatively shifting a beam spot of first laser irradiation from the first substrate end to the second substrate end, spraying a refrigerant to a portion immediately after passing the beam spot to cool the portion, and forming a scribe line having a limited depth using a stress gradient in the depth direction to be generated in the scribe-scheduled line, a step (c) of forming a second early crack on the first substrate end or between the first substrate end and the first early crack, and a step (d) of relatively moving the beam spot of second laser irradiation from the first substrate end to the second substrate end to further deepen or completely split the scribe line.