Abstract: A workpiece holding method for a workpiece having a bowl-shaped warp includes a mounting step of mounting the workpiece on a holding unit having a holding surface, a suction hole opening to the holding surface, and a suction passage for making selective communication between the suction hole and a vacuum source for producing a suction force, the workpiece being mounted on the holding surface of the holding unit, a liquid supplying step of supplying a liquid to the workpiece held on the holding surface so that the liquid flows into a gap defined between the holding surface and the workpiece to fill the gap, and a suction step of bringing the suction hole into communication with the vacuum source to suck the liquid and the workpiece and thereby hold the workpiece through the liquid on the holding surface under suction, after performing the liquid supplying step.

Abstract: An edge trimming apparatus includes a chuck table that causes a ring-shaped groove with an outer diameter smaller than the outer diameter of a wafer to communicate with a suction source to hold under suction a lower surface of the wafer by the ring-shaped groove, a cutting unit that rotates a cutting blade and annularly cuts a circumferential part of the wafer held by the chuck table, and a cleaning unit that cleans a region outside the ring-shaped groove in the upper surface of the table and the upper surface of the table including the ring-shaped groove. The cleaning unit is positioned to the region outside the ring-shaped groove in the upper surface of the table and the upper surface of the chuck table including the ring-shaped groove, and the chuck table is rotated to clean the ring-shaped groove and the upper surface.

Abstract: A workpiece holding method for a workpiece having a bowl-shaped warp includes a mounting step of mounting the workpiece on a holding unit having a holding surface, a suction hole opening to the holding surface, and a suction passage for making selective communication between the suction hole and a vacuum source for producing a suction force, the workpiece being mounted on the holding surface of the holding unit, a liquid supplying step of supplying a liquid to the workpiece held on the holding surface so that the liquid flows into a gap defined between the holding surface and the workpiece to fill the gap, and a suction step of bringing the suction hole into communication with the vacuum source to suck the liquid and the workpiece and thereby hold the workpiece through the liquid on the holding surface under suction, after performing the liquid supplying step.