US Patent 7745311 Working method for an optical device wafer

A dividing method for an optical device wafer includes a protective plate adhering step of releasably adhering the surface of an optical device wafer to the surface of a protective plate, a reverse face grinding step of grinding the reverse face of the optical device wafer, a dicing tape sticking step of sticking the reverse face of the optical device wafer on the surface of a dicing tape, a protective plate grinding step of grinding the reverse face of the protective plate adhered to the optical device wafer stuck on the dicing tape so as to have a predetermined thickness, a laser working step of irradiating a laser beam upon the protective plate along the streets formed on the optical device wafer to carry out laser working, which forms break starting points along the streets, for the protective plate, and a wafer dividing step of applying external force to the protective plate to break the protective plate along the break starting points to break the optical device wafer along the streets thereby to divide the optical device wafer into the individual optical devices.