US Patent 7585751 Wafer dividing method using laser beam with an annular spot

In a wafer dividing method of dividing a wafer into individual devices, the wafer being sectioned by streets to form the devices each made of a laminated body in which an insulating film and a function film are laminated on a front surface of a semiconductor substrate, the method includes a laser processing groove forming step for forming a laser processing groove on the laminated body so as to reach the semiconductor substrate by applying a laser beam formed with an annular spot to the laminated body side of the wafer along the street, the annular spot having an outer diameter larger than a width of a cutting blade and smaller than a width of the street; and a cutting step for allowing a cutting blade to cut the semiconductor substrate of the semiconductor wafer along the laser processing groove formed at the street.