Patent attributes
A wafer laser processing method for forming deteriorated layers in the inside of a wafer having devices which are formed in a plurality of areas sectioned by a plurality of streets formed in a lattice pattern on the front surface along the streets by applying a laser beam along the streets, comprising: a first deteriorated layer forming step for forming a first deteriorated layer along the streets near the front surface of the wafer by applying a laser beam having a wavelength of 1,064 nm from the rear surface side of the wafer along the streets with its focal spot set to a position near the front surface of the wafer; and a second deteriorated layer forming step for forming a second deteriorated layer along the streets at a position closer to the rear surface of the wafer than the first deteriorated layer by applying a laser beam having a wavelength of 1,342 nm from the rear surface side of the wafer along the streets with its focal spot set to a position closer to the rear surface than the first deteriorated layer.
