Patent attributes
A wafer dividing method is provided that includes a protective plate sticking step of sticking the face of the wafer to the face of a protective plate by a pressure sensitive adhesive material whose adhesive force is decreased by an external stimulus; a degeneration layer formation step of throwing a laser beam, which permeates the wafer, along the street to the back side of the wafer, thereby forming a degeneration layer of a thickness corresponding to at least the finished thickness of the device within the wafer, the degeneration layer starting at the face of the wafer; a back grinding step of grinding the back of the wafer to form the wafer into the finished thickness of the device; a wafer support step of sticking the back of the wafer to a surface of a dicing tape mounted on an annular frame; an adhesive force decreasing step of imparting an external stimulus to the pressure sensitive adhesive material, thereby decreasing the adhesive force of the pressure sensitive adhesive material; a protective plate peeling step of peeling the protective plate from the face of the wafer; and a wafer rupture step of imparting an external force to the wafer, thereby rupturing the wafer along the street.
