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.

A silicon carbide ingot is cut using a wire. The silicon carbide ingot has a polytype of 4HSiC. The silicon carbide ingot includes a top surface, a bottom surface opposite to the top surface, and a side surface between the.top surface and the bottom surface. A direction from the bottom surface toward the top surface is a direction parallel to a [0001] direction or a direction inclined by less than or equal to 8 relative to the [0001] direction. In the cutting of the silicon carbide ingot, the silicon carbide ingot is cut from the side surface at a (000-1) plane side along a straight line parallel to a direction within 5 relative to a direction that bisects an angle formed by a [1-100] direction and a [11-20] direction when viewed in the direction from the bottom surface toward the top surface.

A processing apparatus includes: a holding unit that holds a workpiece; a processing mechanism that processes the workpiece held by the holding unit; a processing liquid supplying mechanism that supplies a processing liquid containing an oxidizing agent to at least the workpiece held by the holding unit at the time of processing the workpiece by the processing means; a processing waste liquid recovery section that recovers a processing waste liquid containing the processing liquid supplied from the processing liquid supplying mechanism to the workpiece; a discharge passage through which the processing waste liquid is discharged from the processing waste liquid recovery section to the outside of the processing apparatus; and a waste liquid treatment mechanism that is disposed in the discharge passage and that decomposes the processing liquid contained in the processing waste liquid while the processing waste liquid flows through the discharge passage.

A wafer processing method includes preparing a holding table having a blade clearance portion formed therein so as to correspond to a notch of a wafer, holding the wafer by the holding table so as to make the notch of the wafer correspond to the blade clearance portion of the holding table, reducing the diameter of the wafer by cutting the wafer by a cutting blade along an outer peripheral edge of the wafer in a state in which an end of the cutting blade is positioned below the holding surface of the holding table and therefore removing at least a part of the notch portion, and forming a second notch in the wafer by cutting the wafer in a thickness direction by the cutting blade along the blade clearance portion of the holding table.

A wafer processing method includes preparing a holding table having a blade clearance portion formed therein so as to correspond to a notch of a wafer, holding the wafer by the holding table so as to make the notch of the wafer correspond to the blade clearance portion of the holding table, reducing the diameter of the wafer by cutting the wafer by a cutting blade along an outer peripheral edge of the wafer in a state in which an end of the cutting blade is positioned below the holding surface of the holding table and therefore removing at least a part of the notch portion, and forming a second notch in the wafer by cutting the wafer in a thickness direction by the cutting blade along the blade clearance portion of the holding table.

A saw wire to cut hard and brittle materials is disclosed that comprises a steel wire that is provided with bends with segments in between. The average degree of bending of the bends is between 0.5% and 5%. Such a saw wire has a higher breaking load compared to saw wires having a conventional, higher average degree of bending. A method to measure the curvature is described as well as a process to make the inventive saw wire. The invention is applicable to any shaped saw wire for example a single crimped saw wire, a saw wire with at least two crimps in different planes, a saw wire with crimps rotating in a plane.

A saw wire to cut hard and brittle materials is disclosed that comprises a steel wire that is provided with bends with segments in between. The average degree of bending of the bends is between 0.5% and 5%. Such a saw wire has a higher breaking load compared to saw wires having a conventional, higher average degree of bending. A method to measure the curvature is described as well as a process to make the inventive saw wire. The invention is applicable to any shaped saw wire for example a single crimped saw wire, a saw wire with at least two crimps in different planes, a saw wire with crimps rotating in a plane.

A method for slicing a workpiece with a wire saw which includes a wire row formed by winding a fixed abrasive grain wire having abrasive grains secured to a surface thereof around multiple grooved rollers, the method including feeding a workpiece to the wire row for slicing while allowing the fixed abrasive grain wire to reciprocatively travel in an axial direction thereof, thereby slicing the workpiece at multiple positions aligned in an axial direction of the workpiece simultaneously. The method includes: supplying a coolant for workpiece slicing onto the wire row when the workpiece is sliced with the fixed abrasive grain wire; and supplying a coolant for workpiece drawing, which differs from and has a higher viscosity than the coolant for workpiece slicing, onto the wire row when the workpiece is drawn out from the wire row after the slicing of the workpiece.

A method for slicing a workpiece with a wire saw which includes a wire row formed by winding a fixed abrasive grain wire having abrasive grains secured to a surface thereof around multiple grooved rollers, the method including feeding a workpiece to the wire row for slicing while allowing the fixed abrasive grain wire to reciprocatively travel in an axial direction thereof, thereby slicing the workpiece at multiple positions aligned in an axial direction of the workpiece simultaneously. The method includes: supplying a coolant for workpiece slicing onto the wire row when the workpiece is sliced with the fixed abrasive grain wire; and supplying a coolant for workpiece drawing, which differs from and has a higher viscosity than the coolant for workpiece slicing, onto the wire row when the workpiece is drawn out from the wire row after the slicing of the workpiece.

A saw wire to cut hard and brittle materials is disclosed that comprises a steel wire that is provided with bends with segments in between. The average degree of bending of the bends is between 0.5% and 5%. Such a saw wire has a higher breaking load compared to saw wires having a conventional, higher average degree of bending. A method to measure the curvature is described as well as a process to make the inventive saw wire. The invention is applicable to any shaped saw wire for example a single crimped saw wire, a saw wire with at least two crimps in different planes, a saw wire with crimps rotating in a plane.