Patent ID: 7687373

Claim:
A wafer dividing method of dividing a wafer along lattice-like streets into a plurality of individual devices by laser processing means, the wafer being sectioned by the streets into the devices on the front surface thereof, the method comprising: a wafer holding step for allowing holding means to hold the wafer with a rear surface side thereof opposed to the laser processing means; an electromagnetic irradiation step for emitting an electromagnetic wave, which can penetrate the wafer, onto the front surface side of the wafer to form an image of the streets on the rear surface side; a street detection step for detecting the streets from the rear surface side of the wafer on the basis of the image formed on the rear surface side by the electromagnetic wave that has penetrated the wafer; and a wafer processing step for emitting a laser beam from the laser processing means onto the rear surface side of the wafer along the streets detected in the street detection step.