Patent ID: 9685377
Date: 2017-06-20
CPC Classifications: H01L

Claim:
1. A wafer processing method wherein a wafer having a plurality of scheduled division lines formed in a grating on a front face thereof and having a device formed in each of regions thereof partitioned by the scheduled division lines is divided along the scheduled division lines into individual device chips, the wafer processing method comprising: a protective film forming step of coating liquid-state resin, which is hardened by irradiation of ultraviolet rays thereon, on the front face of the wafer, with the devices thereon, to form a protective film; a protective film hardening step of irradiating ultraviolet rays upon the protective film to harden the protective film; a protective tape adhering step of adhering a protective tape on a front face of the hardened protective film, wherein the protective tape adhering step is performed after the protective film hardening step; a modified layer forming step of irradiating a laser beam of a wavelength having a transparency to the wafer along the scheduled division lines with a focal point thereof positioned in the inside of the wafer to form a modified layer along the scheduled division lines in the inside of the wafer, wherein the modified layer forming step is performed after the protective tape adhering step; and a back face grinding step of grinding, after the protective tape adhering step and the modified layer forming step are carried out, a back face of the wafer while grinding water is supplied to thin the wafer to a given thickness and divide the wafer into the individual device chips along the scheduled division lines using the modified layer as a start point of the break.