Patent ID: 7858496

Claim:
A wafer processing method for dividing a wafer along a plurality of crossing streets formed on the front side of said wafer, said wafer having a device area and a peripheral marginal area surrounding said device area, said device area being composed of a plurality of regions partitioned by said streets, wherein individual devices are respectively formed in said regions of said device area, said wafer processing method comprising: a back grinding step of grinding the back side of said wafer in an area corresponding to said device area to thereby reduce the thickness of said device area to a predetermined finished thickness and to simultaneously form an annular reinforcing portion on the back side of said wafer in an area corresponding to said peripheral marginal area; a wafer supporting step of attaching the back side of said wafer to a dicing tape supported to an annular frame after performing said back grinding step, wherein the adhesive force of said dicing tape can be reduced by an external stimulus; a kerf forming step of cutting the front side of said wafer attached to said dicing tape along each street by using a cutting blade after performing said wafer supporting step, thereby forming a kerf having a depth corresponding to the thickness of said device area along each street to thereby divide said device area into said individual devices; and a peripheral marginal area removing step of applying said external stimulus to said dicing tape at which attached said peripheral marginal area where said annular reinforcing portion is formed after performing said kerf forming step, thereby reducing the adhesive force of said dicing tape, and next peeling off said peripheral marginal area from said dicing tape.