A wire sawing apparatus of one embodiment comprises: a wire for cutting an ingot; an ingot conveyor unit for conveying the ingot to the wire; a nozzle for supplying slurry to the wire; and a dispersed slurry blocking unit disposed above the ingot sawed by the wire, so as to absorb at least a part of the slurry dispersed from the lateral sides of the ingot cut by the wire.

An evaluation method of abrasive grains used in an ingot-cutting slurry includes: an evaluation solution preparation step in which abrasive grains including polishing grains and impurities are dissolved in a solvent to prepare an evaluation solution; a sedimentation step in which a container containing the evaluation solution is left still to settle the polishing grains; a measurement step in which a turbidity of supernatant of the evaluation solution is measured using the measurement device; and an estimation step in which an amount of the impurities is estimated based on the measurement result of the turbidity of the supernatant.

Technique to provide an abrasive regeneration method which, from a used abrasive, can recover an abrasive by an efficient method and can thereafter obtain a high-purity regenerated abrasive by a simple method. This abrasive regeneration method uses an abrasive comprising at least one type of abrasive selected from diamond, boron nitride, silicon carbide, alumina, alumina zirconia, zirconium oxide and cerium oxide. The abrasive regeneration involves a slurry recovery step (A) for recovering an abrasive slurry discharged from a polishing machine, a separation and concentration step (B) for adding an alkaline earth metal salt as an inorganic salt to the recovered abrasive slurry to aggregate the abrasive, and separating and concentrating the abrasive from a mother liquor, an abrasive recovery step (C) for recovering the separated and concentrated abrasive, and a second concentration step (D) for filter-treating the concentrated abrasive.

Abrasive material regeneration method regenerates a cerium oxide abrasive material from a used abrasive material slurry containing the cerium oxide abrasive material and resulting from grinding a grinding subject having silicon as the primary component, characterized by regenerating the abrasive material containing cerium oxide through: a slurry recovery step (A) for recovering an abrasive material slurry discharged from a grinder; an isolation/concentration step (B) for adding a magnesium salt as an inorganic salt to the recovered abrasive material slurry, aggregating the abrasive material under the condition that the pH value of the mother liquor converted to 25 DEG C is at least 6.5 and less than 10.0, and thus isolating and concentrating the abrasive material from the mother liquor; and an abrasive material recovery step (C) for recovering the isolated and concentrated abrasive material.

Semiconductor wafers are produced from a workpiece by means of a wire saw, by feeding the workpiece through an arrangement of wires tensioned between wire guide rollers and divided into wire groups, the wires moving in a running direction producing kerfs as wires engage the workpiece. For each of the wire groups, a placement error of the kerfs of the wire groups determined, and for each of the wire groups compensating movements of the wires of the wire group are induced 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.

Provided are abrasive grains, an evaluation method and a wafer manufacturing method. A predetermined amount of abrasive grains is prepared as an abrasive grain sample group, the grain diameter of individual abrasive grains in the abrasive grain sample group is measured, the number of abrasive grains in the abrasive grain sample group as a whole is counted, abrasive grains having a grain diameter equal to or smaller than a predetermined reference grain e diameter criterion which is smaller than the average grain diameter of the abrasive grain sample are defined as small grains and the number of the small grains is counted, a small grain ratio is calculated as the number ratio of the small grains occupied in the abrasive grain sample group as a whole, and a determination is made as to whether or not the small grain ratio is equal to or smaller than a predetermined threshold value.

A variable-step-distance micro-milling repair cutter path generating method for damage points on a surface of an optical crystal related to a field of optical material and optical element surface repair and includes steps of establishing a mathematical model of a repair profile; determining discrete contact points between a cutter and the repair profile to obtain a cutter contact control point set by a GPR path generating method to control a movement trend of a pseudo-random path; interpolating the cutter position control point set into a spatial curve by a NURBS modeling method; creating a UG curve in a UG software according to the mathematical model, and using the UG curve as the repair path to perform a machining process simulation. The method has good elimination effects on cutter marks with constant period and improves the ability of the KDP crystal to resist strong laser damage.

A crystal ingot cutting device and a crystal ingot cutting method are provided. The crystal ingot cutting device includes a driving unit, at least one cutting wire and a plurality of abrasive particles. The cutting wire is connected to the driving unit, wherein the driving unit drives a crystal ingot to move to the cutting wire and drives the cutting wire to reciprocate. A moving speed of the crystal ingot is 10˜700 μm/min, and a reciprocating speed of the cutting wire is 1800˜5000 m/min. The plurality of abrasive particles are arranged on the cutting wire, and a particle size of each abrasive particle is 5˜50 μm.

A method for slicing a workpiece includes feeding and slicing a workpiece held by a workpiece holder with a bonding member therebetween, while reciprocatively traveling a fixed abrasive grain wire wound around multiple grooved rollers to form a wire row, so that the workpiece is sliced at multiple positions simultaneously. The bonding member has a grindstone part. The method includes, after the workpiece is sliced and before it is drawn out from the wire row, a fixed-abrasive-grain removal step of pressing the wire against the grindstone to remove fixed abrasive grains from the wire while reciprocatively traveling. In the fixed-abrasive-grain removal step, the wire rate is 100 m/min. or less, and the load on each line of the wire is 30 g or more. The method prevents a sliced workpiece from catching a wire and from causing saw mark and wire break in drawing out the wire after slicing.

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 a plurality of grooved rollers, the wire being fed from one of a pair of wire reels and taken up by another, the method including feeding a workpiece to the row for slicing while allowing the wire to reciprocate and travel in an axial direction, thereby slicing the workpiece at a plurality of positions aligned in an axial direction of the workpiece simultaneously. Prior to slicing, an abrasive-grain abrading step wherein the wire is allowed to travel without slicing the workpiece, allowing the wire to rub against itself within the reels, and dressing its surface for 30 minutes or more. The method can dress a fixed abrasive grain wire at low cost and suppress thickness unevenness of wafers.