Abstract: A method of processing a wafer includes a composite substrate forming step of joining a face side of a wafer and a surface of a support substrate to each other with a joint member interposed therebetween, a grinding step of grinding a reverse side of the wafer of the composite substrate to thin down the wafer to a finished thickness, a transfer member affixing step of affixing a transfer member to the reverse side of the wafer, a joint member breaking step of breaking the joint member by applying a laser beam having a wavelength transmittable through the support substrate and absorbable by the joint member to the composite substrate from another surface side of the support substrate, and a transferring step of peeling off the support substrate from the wafer and transferring the wafer to the transfer member.

Abstract: A lift-off method includes joining a transfer substrate to a face side of an optical device layer of an optical device wafer with a joining member interposed therebetween, thereby making up a composite substrate, applying a pulsed laser beam having a wavelength transmittable through the epitaxy substrate and absorbable by a buffer layer, from a reverse side of the epitaxy substrate of the optical device wafer, thereby breaking the buffer layer, and an optical device layer transferring step of peeling off the epitaxy substrate from the optical device layer and transferring the optical device layer to the transfer substrate. The optical device layer transferring step includes the step of applying a bending moment to an area of the composite substrate that includes an outer peripheral portion thereof while holding an area of the composite substrate that includes a central portion thereof.

Abstract: A chuck table holds a workpiece having a warp. The chuck table includes a suction holding member having a suction holding surface for holding the workpiece under suction, and an annular seal member provided around the outer circumference of the suction holding member for supporting a peripheral portion of the workpiece. The annular seal member is formed from an elastic member. The upper surface of the annular seal member is set higher in level than the suction holding surface according to the warp of the workpiece. In holding the workpiece on the chuck table under suction, vacuum leaking from the gap between the workpiece and the suction holding surface due to the warp of the workpiece is applied to the space defined by the workpiece and the annular seal member, thereby elastically deforming the annular seal member to flatten the upper surface of the workpiece.

Abstract: A chuck table holds a workpiece having a warp. The chuck table includes a suction holding member having a suction holding surface for holding the workpiece under suction, and an annular seal member provided around the outer circumference of the suction holding member for supporting a peripheral portion of the workpiece. The annular seal member is formed from an elastic member. The upper surface of the annular seal member is set higher in level than the suction holding surface according to the warp of the workpiece. In holding the workpiece on the chuck table under suction, vacuum leaking from the gap between the workpiece and the suction holding surface due to the warp of the workpiece is applied to the space defined by the workpiece and the annular seal member, thereby elastically deforming the annular seal member to flatten the upper surface of the workpiece.