An abrasive article including a substrate having an elongated body, a tacking layer overlying the substrate, and a first type of abrasive particle overlying the tacking layer and defining a first abrasive particle concentration at least about 10 particles per mm of substrate.

A method for cutting a silicon ingot includes cutting a silicon ingot by causing a fixed-abrasive-grain wire to run at a speed in which the maximum speed is 1,200 m/minute or higher while supplying a coolant in which the percentage of water is more than 99%.

A method of resuming operation of a wire saw in which slicing of a workpiece is suspended due to a wire break, including processes of: imparting axial reciprocating motion to a wire while supplying a new line of the wire; and slicing the workpiece into wafers by moving the workpiece downwardly to press the workpiece against the reciprocating wire while supplying a slicing slurry to the wire, the method includes: repairing the broken wire after suspending the slicing of the workpiece before resuming the slicing of the workpiece; and preparing for the slicing in that a diameter of the repaired wire at a position at which the workpiece is to be sliced is matched to the diameter of the wire just before occurrence of the wire break. The method can inhibit the formation of grooves in wafers sliced after the resumption and reduce low-quality production wafers.

A process for manufacturing an abrasive wire formed by abrasive particles held on a central core by a binder comprises depositing abrasive particles on the central core, each particle comprising a magnetic material that has a relative permeability greater than 50 and that represents at least 1% of the volume of the abrasive particle, and depositing binder on the central core to keep the abrasive particles attached to it. The core has south poles and north poles alternating along either its circumference or its length.

The present invention is a fixed-abrasive-grain wire including a core wire and abrasive grains fixed on a surface of the core wire, wherein an abrasive grain density is 1200 grains/mm.sup.2 or more, where the abrasive grain density is the number of the abrasive grains per unit area on the surface of the core wire, and 2% or less of all distances between centroids of the abrasive grains are equal to or shorter than an average circle equivalent diameter of the whole abrasive grains. There can be provided a fixed-abrasive-grain wire, a wire saw, and a method for slicing a workpiece that can suppress meandering of the fixed-abrasive-grain wire during slicing a workpiece and improve TTV and warp of wafers sliced from the workpiece.

A method for simultaneously cutting a multiplicity of slices from a cylindrical workpiece, along strictly convex cutting faces, by supplying a suspension of hard substances in a carrier liquid, as cutting medium, to wire portions, while the wire portions, having a longitudinal tension, define a relative motion to the workpiece as a result of wire guide roller rotation with continual alternation between a first direction of rotation and a second direction of rotation, which is opposite to the first direction of rotation, wherein, during the rotation in the first direction, the wire is moved a first length, and during the rotation in the second direction, the wire is moved a second length, and the second length is shorter than the first, and at the cutting operation start a first longitudinal wire tension is greater than a second longitudinal tension at the end.

The present invention is a method for slicing a workpiece, including: forming a wire row by a wire spirally wound between a plurality of wire guides and traveling in an axial direction, and pressing a workpiece against the wire row while supplying a processing liquid containing abrasive grains to a contact portion between the workpiece and the wire, wherein a used portion of the abrasive grains are subjected to a treatment with a mixed liquid of sulfuric acid and hydrogen peroxide, and the abrasive grains subjected to the treatment are reused for the slicing of a workpiece. This makes it possible to slice a workpiece with suppressing contamination of a wafer with metal impurities when abrasive grains are reused in slicing a workpiece by use of a wire saw.

Semiconductor wafers having a subsurface-referenced nanotopography of the upper side surface of less than 6 nm, expressed as a maximum peak-to-valley distance on a subsurface and referenced to subsurfaces with an area content of 25 mm25 mm, are produced from a workpiece by feeding the workpiece through a wire web tensioned between wire guide rollers and divided into wire groups, the wires producing kerfs as the wires engage the workpiece. For each of the wire groups, a placement error of the kerfs of the wire groups is used to compensate movements of the wires of the wire group as a function of the placement error, in a direction perpendicular to the running direction of the wires during feeding of the workpiece through the arrangement of wires, by activating at least one drive element.

The cutting-off and grinding integrated machine includes a machine body, a feeding component, a blanking component, a cutting-off component, a grinding component, and a transfer component. The cutting-off component, the feeding component, the grinding component and the blanking component are juxtaposed in the machine body in a width direction of the machine body; the grinding component includes plane grinding components and chamfer grinding components, the chamfer grinding components and the plane grinding components are integrally disposed, and the feeding component and the blanking component are both movable in a length direction of the machine body; and the transfer component includes a manipulator movable in the width and height directions of the machine body, and a blanking position of the feeding component, a feeding position of the blanking component and machining positions of the cutting-off component and the grinding component are all located on a moving path of the manipulator.