MANUFACTURE OF SEMICONDUCTOR SUBSTRATE WITH INSULATING FILM FORMED BY USING LASER IRRADIATION

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor substrate with an insulating film using a laser irradiation, which can cut dividedly the substrate in a lattice type, with good accuracy and at a quick speed. SOLUTION: Grooves 2 extending over from the end on one side of the ends of the surface of an Si substrate 1 to the other end of the substrate 1 are formed in at least one surface of the substrate 1 as slicing lines, an insulating film 3 covering the surface of this substrate is formed, CO2 laser beams L irradiated on this film 3 are made to extend along the grooves 2 to move the laser beams L, whereby cracks due to a thermal stress are developed in the directions of movement of these CO2 laser beams L to slice the substrate 1.