| 摘要 |
PROBLEM TO BE SOLVED: To provide a processing method for wafer, whereby a wafer can be divided into individual devices without making a cut face of the wafer, which is near the back of the wafer, rough.SOLUTION: A processing method for a wafer comprises: a modified layer formation step in which a modified layer is formed in a wafer 2 along a dividing line by emitting a laser beam of wavelength that transmits through the wafer 2 along the dividing line from the back side of the wafer; and a dividing step in which external force is applied to the wafer, thereby dividing it into individual devices along the dividing line along which the modified layer is formed. The modified layer formation step includes: a first modified layer formation step in which a laser beam condensation point is located near the back of the wafer and a first modified layer 210 is formed; and a second modified layer formation step in which while a laser beam condensation point is located on the surface side of the wafer, away from the first modified layer, the laser beam is emitted thereto, and then, while the condensation point is sequentially moved to the area reaching the first modified layer, a plurality of second modified layers 220 are formed in layers. |
