Abstract: A peeling apparatus includes a holding table that holds an ingot, a water supply unit that forms a layer of water on an upper surface of the ingot, an ultrasonic unit that applies an ultrasonic wave to the upper surface of the ingot through the layer of water, a peeling confirmation unit that confirms peeling-off of a wafer to be manufactured, a wafer delivery unit that lowers a suction pad having a suction surface facing the upper surface of the ingot, to hold the wafer to be manufactured on the suction surface under suction, and delivers the wafer from the ingot, and a controller. After the peeling-off of the wafer is confirmed by the peeling confirmation unit, the controller positions the water supply unit, the ultrasonic unit, and the peeling confirmation unit at retracted positions and operates the wafer delivery unit to deliver the wafer from the ingot.

Abstract: A conveying apparatus for conveying a plate-shaped workpiece includes a holding unit that holds the plate-shaped workpiece under suction, a moving unit that moves in a vertical direction together with the holding unit, a detection unit that detects that the holding unit has moved downward and made contact with the plate-shaped workpiece, and a control unit that performs control to stop a downward movement of the moving unit when the detection unit detects that the holding unit has made contact with the plate-shaped workpiece.

Abstract: An ultrasonic wave is applied to an upper surface of an ingot via a liquid layer, in a state in which an outer circumferential region of a lower surface of the ingot is sucked. A lower side around an outer circumferential arc-shaped portion of the lower surface of the ingot is open so that liquid that serves as a medium of the ultrasonic wave does not collect around the outer circumferential arc-shaped portion of the lower surface of the ingot. As a result, a peel-off layer formed in the ingot is not immersed in liquid when an ultrasonic wave is applied to the upper surface of the ingot via the liquid layer. Consequently, even when the ingot becomes thin, the ingot can be separated at the peel-off layer, and a wafer can be peeled off from the ingot.

Abstract: Precipitation-hardenable, nitrided aluminum alloys are produced by forming an alloy of aluminum metal at a temperature up to about 800.degree. C with a nitrided mother alloy of a specified composition which has been nitrided at a temperature of 800.degree. to 1,200.degree. C. The aluminum alloys are made precipitation-hardenable by the incorporation therein of a precipitation-hardening component such as copper, zinc and/or magnesium, and the precipitation-hardening component can be contained in the mother alloy undergoing nitridation.