| 摘要 |
The present invention provides a wafer processing method capable of suppressing damage, caused by transmitted light, to a device on the surface of a wafer when forming a reforming layer in the wafer by emitting a pulse laser beam of which wavelength is set in a range of 1300-1400 nm for a silicon wafer. The wafer processing method, processing a silicon wafer formed as multiple devices are divided on the surface by multiple division-expected lines, includes: a wavelength setting step of setting the wavelength of a pulse laser beam, having transmission to the wafer, in a ranges of 1300 nm-1400 nm; a reforming layer forming step of emitting the pulse laser beam to an area from the rear surface of the wafer to the division-expected lines by placing a light concentration point of the pulse laser beam in the wafer after the wavelength setting step, and relatively transferring a maintaining unit and a laser beam emitting unit to form a reforming layer in the wafer; and a division step of dividing the wafer along the division-expected lines from the reforming layer, used as a division starting point, by applying external force to the wafer after the reforming layer forming step. The reforming layer forming step includes: a step of forming a first reforming layer by emitting a first pulse laser beam of which energy per pulse is relatively small; and a step of forming a second reforming layer, overlapped with the first reforming layer, by emitting a second pulse laser beam of which energy per pulse is relatively large. |
