Methods of recycling silicon swarf into electronic grade polysilicon or metallurgical-grade silicon are described herein are described. In an example, a method includes cutting a silicon ingot and recovering silicon swarf having a first purity from the cutting process. The recovered silicon is purified in an upgraded metallurgical silicon process to produce electronic grade polysilicon particles having a second purity higher than the first purity. The upgraded metallurgical silicon process can include dissolving the recovered silicon particles in a molten aluminum metal smelt.

A roller module is used for driving a sawing wire to slice an ingot into multiple wafers, and includes two spaced apart main rollers and an auxiliary roller. Each main roller has a rotating axis and a diameter. An imaginary horizontal plane is defined to pass through the rotating axes of the main rollers. Two imaginary vertical planes are defined to be perpendicular to the imaginary horizontal plane and respectively pass through the rotating axes of the main rollers. The auxiliary roller is disposed above the imaginary horizontal plane and between the imaginary vertical planes. An uppermost side of the auxiliary roller is not lower than an uppermost side of each main roller. The auxiliary roller has a diameter smaller than one half of that of each main roller.

Provided is an indium phosphide substrate, a semiconductor epitaxial wafer, and a method for producing an indium phosphide substrate, which can satisfactorily suppress warpage of the back surface of the substrate. The indium phosphide substrate includes a main surface for forming an epitaxial crystal layer and a back surface opposite to the main surface, wherein the back surface has a WARP value of 3.5 μm or less, as measured with the back surface of the indium phosphide substrate facing upward.

Provided is an indium phosphide substrate, a semiconductor epitaxial wafer, and a method for producing an indium phosphide substrate, which can satisfactorily suppress warpage of the back surface of the substrate. The indium phosphide substrate includes a main surface for forming an epitaxial crystal layer and a back surface opposite to the main surface, wherein the back surface has a BOW value of −2.0 to 2.0 μm, as measured with the back surface of the indium phosphide substrate facing upward.

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 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.

Methods of recycling silicon swarf into electronic grade polysilicon or metallurgical-grade silicon are described herein are described. In an example, a method includes cutting a silicon ingot and recovering silicon swarf having a first purity from the cutting process. The recovered silicon is purified in an upgraded metallurgical silicon process to produce electronic grade polysilicon particles having a second purity higher than the first purity. The upgraded metallurgical silicon process can include dissolving the recovered silicon particles in a molten aluminum metal smelt.

Methods of recycling silicon swarf into electronic grade polysilicon or metallurgical-grade silicon are described herein are described. In an example, a method includes cutting a silicon ingot and recovering silicon swarf having a first purity from the cutting process. The recovered silicon is purified in an upgraded metallurgical silicon process to produce electronic grade polysilicon particles having a second purity higher than the first purity. The upgraded metallurgical silicon process can include dissolving the recovered silicon particles in a molten aluminum metal smelt.

An object is to provide a SiC wafer in which a detection rate of an optical sensor can improved and a SiC wafer manufacturing method.

The method includes: a satin finishing process S141 of satin-finishing at least a back surface 22 of a SiC wafer 20; an etching process 21 of etching at least the back surface 22 of the SiC wafer 20 by heating under Si vapor pressure after the satin finishing process S141; and a mirror surface processing process S31 of mirror-processing a main surface 21 of the SiC wafer 20 after the etching process S21. Accordingly, it is possible to obtain a SiC wafer having the mirror-finished main surface 21 and the satin-finished back surface 22.