| 摘要 |
PROBLEM TO BE SOLVED: To provide a wafer processing method capable of suppressing a device on a surface of a silicon wafer from being damaged by transmitted light when forming a modified layer inside the wafer by irradiating the silicon wafer with a pulse laser beam of a wavelength set within a range from a 1300 nm to 1400 nm.SOLUTION: A wafer processing method for dividing a silicon wafer 11 formed by partitioning a plurality of devices into a surface of the wafer by division schedule lines 13a comprises the steps of: setting a wavelength of a pulse laser beam having permeability (wavelength setting step); positioning a condensing point of the pulse laser beam at the inside of the wafer and forming a first modified layer 19a by irradiating the region corresponding to the division schedule lines from a rear surface 11b of the wafer with the pulse laser beam (first modified layer 19a forming step); displacing the wafer by a prescribed distance from the first modified layer in a direction orthogonal to a feeding direction and forming a second modified layer 19b alternately with the first modified layer by irradiating the same division schedule lines with the pulse laser beam (second modified layer 19b forming step); and applying external force to the wafer and dividing the wafer using the first and second modified layers as a division start point (dividing step).SELECTED DRAWING: Figure 7 |
