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 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 wire saw apparatus including: a wire row formed of a wire wound around a plurality of wire guides and reciprocatively travels in an axial direction; a nozzle from a coolant or slurry is supplied to the wire; and a workpiece feed mechanism presses a held workpiece against the wire row, the wire saw apparatus slice the workpiece into a wafer shape by pressing the workpiece held by the workpiece feed mechanism against the wire row and feeding it for slicing while supplying the coolant or the slurry from the nozzle to the wire, the wire saw apparatus nozzle is arranged above the wire row to be orthogonal to the wire row, and windbreak plates are arranged on both left and right sides of the arranged nozzle seen from an axial direction.

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.

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 m 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 m, as measured with the back surface of the indium phosphide substrate facing upward.

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 slicing method and a slicing apparatus for an ingot are provided. The slicing method for the ingot comprises: setting an ingot on an ingot-feeding device; descending the ingot by the ingot-feeding device and loosening a diamond wire synchronously such that the ingot is surrounded with the diamond wire; and tightening the diamond wire to begin to slice after the ingot is descended to a cooling tank. The slicing method and the slicing apparatus for the ingot of the present disclosure could raise the slicing speed and reduce the temperature difference from a slicing area to a non-slicing area so that the wrap of a silicon chip is improved.

A wire supplying and receiving device includes a moving unit including a rail along a first horizontal direction, a first wire winding unit disposed on the rail and rotatable about an axis parallel to the first horizontal direction, and a second wire winding unit on the rail and rotatable about the axis. At least one of the first and second wire winding units is movable along the first horizontal direction. The wire supplying and receiving device is convertible between a connected state, where the first and second wire winding units are adjacent to each other, and a disconnected state, where the first and second wire winding units are spaced apart from each other. An ingot slicing wire saw and a method for slicing ingot are also provided.

This wire saw machine having a dust collecting apparatus comprises a main roller for moving a wire by rotation; a first pulley system including a first upper dust collecting roller, a first lower dust collecting roller, and a first support roller; a second pulley system including a second upper dust collecting roller, a second lower dust collecting roller, and a second support roller; and a dust collecting unit which is provided under the first pulley system and the second pulley system to collect foreign substances that escape from the first pulley system and the second pulley system.