Abstract: A rotation controlling section of a control unit calculates a maximum thicknesswise difference in a wafer by using a noncontact thickness measuring instrument, and if the maximum thicknesswise difference exceeds a tolerance, relatively changes a rotational speed of a chuck table relative to a rotational speed of a spindle. This can shift a rotational speed ratio, which is a ratio between the rotational speed of the spindle and the rotational speed of the chuck table, from an integer. Therefore, the maximum thicknesswise difference can be made small through spark-out processing. As a result, cyclic variations in thickness value of the wafer are reduced, enabling planarization of a ground surface of the wafer.

Abstract: A rotation controlling section of a control unit calculates a maximum thicknesswise difference in a wafer by using a noncontact thickness measuring instrument, and if the maximum thicknesswise difference exceeds a tolerance, relatively changes a rotational speed of a chuck table relative to a rotational speed of a spindle. This can shift a rotational speed ratio, which is a ratio between the rotational speed of the spindle and the rotational speed of the chuck table, from an integer. Therefore, the maximum thicknesswise difference can be made small through spark-out processing. As a result, cyclic variations in thickness value of the wafer are reduced, enabling planarization of a ground surface of the wafer.

Abstract: A grinding apparatus includes a holding table that holds a wafer, a grinding unit that grinds an exposed surface of the wafer held by the holding table, a detecting unit that detects a physical quantity used for determination of the state of exposure of a separation surface of the wafer, and a control unit having an exposure determining unit that determines the state of exposure of the separation surface on the basis of the physical quantity detected by the detecting unit.

Abstract: A grinding method for grinding a workpiece includes a first grinding step of grinding the workpiece in such a manner that an outer circumferential part of the workpiece becomes thinner than a central part of the workpiece, a measurement step of measuring the thickness of the workpiece at the outer circumferential part, and a second grinding step of grinding the workpiece. In the second grinding step, the grinding is started from the central part of the workpiece and the grinding is ended when the workpiece reaches a finished thickness decided based on the thickness of the workpiece at the outer circumferential part measured in the measurement step.