| 摘要 |
PROBLEM TO BE SOLVED: To provide a wafer processing method of processing a wafer of silicon on which plural devices are formed while compartmented by plural parting scheduled lines, the method suppressing transmitted light from damaging the devices on the surface of the wafer when a reformed layer is formed in the wafer by irradiating silicon wafer with a pulse laser beam having a wavelength having transmissivity to the silicon wafer.SOLUTION: When the convergence point of a pulse laser beam having a wavelength having transmissivity to a wafer 11 is positioned in the wafer, a reformed layer is formed from the back surface of the wafer, and external force is applied to the wafer to part the wafer with the reformed layer set as a parting starting point, a part 77 of the pulse laser beam is cut out in an area extending from the center of the pulse laser beam to be applied to the wafer in the formation of the reformed layer to an outer periphery at the downstream side in the feeding direction, thereby positioning the convergence point of the pulse laser beam inside the wafer.SELECTED DRAWING: Figure 6 |
