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.

A silicon wafer forming method includes: a block ingot forming step of cutting a silicon ingot to form block ingots; a planarizing step of grinding an end face of the block ingot to planarize the end face; a separation layer forming step of applying a laser beam of such a wavelength as to be transmitted through silicon to the block ingot, with a focal point of the laser beam positioned in the inside of the block ingot at a depth from the end face of the block ingot corresponding to the thickness of the wafer to be formed, to form a separation layer; and a wafer forming step of separating the silicon wafer to be formed from the separation layer.

Systems and methods are described for controlled crack propagation in a material using ultrasonic waves. A first stress in applied to the material such that the first stress is below a critical point of the material and is insufficient to initiate cracking of the material. A controlled ultrasound wave is then applied to the material causing the total stress applied at a crack tip in the material to exceed the critical point. In some implementations, the controlled cracking is used for wafering of a material.

Systems and methods are described for controlled crack propagation in a material using ultrasonic waves. A first stress in applied to the material such that the first stress is below a critical point of the material and is insufficient to initiate cracking of the material. A controlled ultrasound wave is then applied to the material causing the total stress applied at a crack tip in the material to exceed the critical point. In some implementations, the controlled cracking is used for wafering of a material.

Provided is a cutting method of cutting a workpiece by using a cutting apparatus including a chuck table configured to hold the workpiece and a cutting unit having a cutting blade configured to cut the workpiece held by the chuck table and an ultrasonic vibrator configured to ultrasonically vibrate the cutting blade in a radial direction of the cutting blade. The cutting method includes a holding step of holding the workpiece by the chuck table, and a cutting step of performing ultrasonic cutting that cuts the workpiece by the cutting blade vibrated ultrasonically and normal cutting that cuts the workpiece by the cutting blade not vibrated ultrasonically on the same cutting line of a plurality of cutting lines set on the workpiece.

A tool unit applied to ultrasonic machining, includes an amplitude transformer, a machining head and a connecting portion. The machining head has a micron-sized array structure. With the connecting portion, the amplitude transformer and the machining head are assembled together and the connecting portion has a change in shape. The machining head includes a substrate and at least one diamond layer. An upper surface of substrate touches the amplitude transformer or the connecting portion. And the diamond layer is disposed on an lower surface of substrate. The material of the substrate is selected from a group of a steel material with thermal expansion coefficient ranged from 10.70×10.sup.−6K.sup.−1 to 17.30×10.sup.−6K.sup.−1, tungsten carbide and combination thereof. The material of the diamond layer is selected from a group of a diamond material with thermal expansion coefficient ranged from 1.00×10.sup.−6K.sup.−1 to 2.50×10.sup.−6K.sup.−1, a polycrystalline diamond, a diamond sintered body and combination thereof.

An ultrasonic resonator support structure 10 including a holder 17 supports an ultrasonic resonator 16 at both sides such that the ultrasonic resonator 16 is rotatable to the holder 17. The ultrasonic resonator 16 includes an ultrasonic horn 13 with a machining tool 12 attached, and a first booster 14 and a second booster 15 coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn 13. The holder 17 has a rolling bearing mechanism 18 that rotatably supports the first booster 14 side of the ultrasonic resonator 16 and a gas bearing mechanism 19 that rotatably supports the second booster 15 side of the ultrasonic resonator 16.

Implementations of methods of thinning a semiconductor substrate may include: providing a semiconductor substrate having a first surface and a second surface opposing the first surface, the semiconductor substrate having a thickness between the first surface and the second surface. The method may further include inducing damage into a portion of the semiconductor substrate at a first depth into the thickness forming a first damage layer, inducing damage into a portion of the semiconductor substrate at a second depth into the thickness forming a second damage layer, and applying ultrasonic energy to the semiconductor substrate. The method may include separating the semiconductor substrate into three separate thinned portions across the thickness along the first damage layer and along the second damage layer.

A peeling apparatus includes: an ingot holding unit holding an ingot with an ingot portion corresponding to a wafer being faced up; an ultrasonic wave oscillating unit which has an end face facing the ingot portion corresponding to the wafer and oscillates an ultrasonic wave; a water supplying unit supplying water to an area between the ingot portion corresponding to the wafer and the end face of the ultrasonic wave oscillating unit; and a peeling unit that holds the ingot portion corresponding to the wafer with suction and peels off the wafer from the ingot.

A multi-line cutting method, a multi-line cutting apparatus and use thereof, a semiconductor material and a power device. The multi-line cutting method includes following steps: configuring a line spool for winding cutting lines to vibrate under the excitation action of ultrasonic waves; and vibrating the cutting lines to cut an object to be cut under the conveying action of the line spool. The vibration of the cutting line under the excitation action of the ultrasonic waves can increase the energy of the cutting lines, enhance the cutting capability of the cutting lines, reduce the abrasion of the cutting lines, and force abrasive materials to impact and grind said object at high frequency and speed, and the chip removal speed is high, so that the surface curvature, the surface warpage, and the total thickness deviation of a product obtained after cutting are all small, and the cutting quality is high.