Laser processing method and semiconductor chip

A LASER PROCESSING METHOD IS PROVIDED, CAPABLE OF HIGHLY PRECISELY CUTTING IN PARTICULAR A LAMINATION SECTION WHEN CUTTING A SUBSTRATE ON WHICH THE LAMINATION SECTION INCLUDING PLURAL FUNCTIONAL DEVICES IS FORMED. IN A STATE IN WHICH A PROTECTIVE TAPE (22) IS ADHERED TO A SURFACE (16A) OF A LAMINATION SECTION (16), BY IRRADIATING A BACKSIDE (4B) OF A SUBSTRATE (4) AS A LASER BEAM INCIDENT SURFACE WITH LASER BEAMS (L), A MODIFIED REGION (7) IS FORMED INSIDE THE SUBSTRATE (4) ALONG A CUTTING SCHEDULED LINE AND A CRACK (24) EXTENDING FROM THE SURFACE SIDE END PORTION (7A) OF THE MODIFIED REGION (7) TO A SURFACE (4A) OF THE SUBSTRATE (4) IS GENERATED. THEN, IN A STATE IN WHICH THERE EXISTS THE CRACK (24) THUS GENERATED, IF AN EXPANDABLE TAPE IS ADHERED TO THE BACKSIDE (4B) OF THE SUBSTRATE (4) AND EXPANDED, IT IS POSSIBLE TO PRECISELY CUT NOT ONLY THE SUBSTRATE (4) BUT ALSO THE LAMINATION SECTION (16) ON THE CUTTING SCHEDULED LINE, THAT IS, INTERLAYER INSULATING FILMS (17A) AND (17B).