Abstract: A method of grinding the notch of a thin workpiece, for example, a semiconductor wafer in the circumferential direction and the thickness direction by arranging a rotating disk-form grinding wheel and a semiconductor wafer to be ground with said wheel in such positions that the respective planes orthogonally cross with each other, moving said wheel in an axial direction of the spindle or rotating said semiconductor wafer upon the center thereof, moving said semiconductor wafer in a direction of approach to or alienation from said wheel, and moving said wheel in a direction to cross orthogonally with said axial line direction and direction of approach to or alienation from said wheel, and an apparatus therefor.

Abstract: An apparatus equipped with a round cutter, a rotation drive mechanism for the cutter, a workpiece stand, a rotary servo-mechanism for rotating the workpiece stand, a rectilinear servo-mechanism for letting the workpiece stand get near to or away from the cutter, an input device for enabling an input operation of at least a diameter or a radius of the cutter, a diameter or a radius of the workpiece, a length of a straight portion of an oriental flat of the workpiece and a radius of curvature of a circular-arc portion at its both sides, and a computer computing a distance between a rotation center of the workpiece and a locus generated by a rotation center of the cutter which revolves while making contact with and relatively to the orientation flat of the workpiece forming a machining standard, as a function in relation to a rotation angle of the workpiece, previously memorizing its operation program and electrically connected to the rotary sevo-mechanism, the rectilinear servo-mechanism and the input device.