| 摘要 |
PROBLEM TO BE SOLVED: To provide a wafer processing method capable of dividing a wafer in which devices are formed of a functional layer laminated on a surface of a substrate along a plurality of streets partitioning the device without peeling a functional layer on the device side.SOLUTION: A wafer processing method for dividing a wafer in which devices are formed of a functional layer laminated on a surface of a substrate along a plurality of streets partitioning the device includes the steps of: separating the functional layer by forming two laser processing grooves reaching the substrate by irradiating the wafer with a laser beam along both sides of the streets (functional layer separating step); and forming a division groove in the functional layer and the substrate by irradiating the central parts of the two laser processing grooves formed along the streets (division groove forming step). A wavelength of the laser beam to be irradiated in the functional layer separating step has absorptivity to a passivation film and is set to not more than 300 nm. |
