A method cuts semiconductor wafers. The method includes: cutting a semiconductor ingot into a workpiece; and sawing the workpiece into slices using a wire grid having a fixed abrasive grain wire, while moving workpiece towards the wire grid. At a first contact of the workpiece with the wire grid, an initial cutting speed is less than 2 mm/min, coolant flow is less than 0.1 l/h and a wire speed is greater than 20 m/s. The workpiece is then guided through the wire grid until a first cutting depth is reached, and then the coolant flow is increased to at least 2000 l/h. The cutting speed is reduced to less than 70% of the initial cutting speed between the first contact of the workpiece with the wire grid up to a cutting depth of half a diameter of the cylinder, and is then increased.

The present invention provides a control method to epitaxial growth monolayer graphene, in which a monolayer graphene is epitaxially grown on a non-polar crystal face at arbitrary angle of a non-polar crystal face SiC substrate, thereby utilizing the non-polar crystal face to manipulate the electrical transport properties of graphene. A monolayer graphene having ballistic transport properties can be epitaxially grown at arbitrary angle of non-polar crystal face SiC substrate by the above-mentioned control method.

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 wire saw apparatus including: a plurality of wire guides; a wire row formed of a wire which is wound around the plurality of wire guides and configured to reciprocatively travel in an axial direction; a nozzle configured to supply a coolant or slurry to the wire; a workpiece-holding portion configured to suspend and hold a workpiece plate having a workpiece bonded thereto with a beam interposed therebetween; a workpiece-feeding mechanism configured to press the workpiece against the wire row; and a mechanism configured to adjust a parallelism of axes of the plurality of wire guides around which the wire row is formed. Thereby, a wire saw apparatus and a method for manufacturing a wafer are provided which enable manufacturing of a wafer having any warp shape by controlling a warp in a wire travelling direction of a sliced workpiece.

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 multi-line cutting method, a multi-line cutting apparatus and use thereof, a semiconductor material and a power device. The multi-line cutting method includes following steps: configuring a line spool for winding cutting lines to vibrate under the excitation action of ultrasonic waves; and vibrating the cutting lines to cut an object to be cut under the conveying action of the line spool. The vibration of the cutting line under the excitation action of the ultrasonic waves can increase the energy of the cutting lines, enhance the cutting capability of the cutting lines, reduce the abrasion of the cutting lines, and force abrasive materials to impact and grind said object at high frequency and speed, and the chip removal speed is high, so that the surface curvature, the surface warpage, and the total thickness deviation of a product obtained after cutting are all small, and the cutting quality is high.

A multiplicity of slices are simultaneously sliced from a workpiece during a slicing operation using a wire saw. A non-linear pitch function dTAR(WP) is selected dependent on a target thickness value function TTAR(WP), a pitch function dINI(WP) and a thickness value function TINI(WP), dTAR(WP) and adjacent grooves in the wire guide rollers are assigned a pitch at a position WP during the slicing operation, TINI(WP) slices which are obtained during a plurality of preceding slicing operations by means of the wire saw at the position WP are assigned a thickness value, dINI(WP), adjacent grooves in the wire guide rollers at the position WP are assigned a pitch during the preceding slicing operations, TTAR(WP) slices which are sliced off during the slicing operation at the position WP are assigned a target thickness value, WP denoting the axial position of the adjacent grooves with respect to the axes of the wire guide rollers.

The present invention provides a monocrystalline SiC substrate with an asymmetric shape for enhancing substrate stiffness against thermal induced deformations, the substrate comprising: a main region, and an asymmetric region located at a peripheral region of the substrate and adjacent to the main region, wherein the asymmetric region is inclined inwards, relative to the main region, to provide an asymmetric shape to the substrate. The present invention also provides a method of producing one or more substrates with an asymmetric shape, comprising: performing a multi-wire sawing process in which one or more substrates are cut with an wire-sawing web from an ingot placed on a stage, and cutting the one or more substrates with the asymmetric shape by controlling a relative movement between the wire-sawing web and the stage, the relative movement causing the wire-sawing web to describe a non-linear sawing path across the ingot to cut the asymmetric shape.

A method of manufacturing a hexagonal Group-III nitride semiconductor plate crystal using a crystal cutting wire. where the hexagonal semiconductor crystal has one principal face on one side and another principal face on an opposite side, and the hexagonal semiconductor crystal is cut by causing the crystal cutting wire to move so as to (i) divide the one principal face and the another principal face and (ii) satisfy conditions of Expressions (A) and (B):
25°<α≤90°  Expression (A); and
β=90°±5°  Expression (B) where α represents an angle formed by a c axis of the hexagonal Group-III nitride semiconductor crystal and a normal line of a crystal face cut out by the wire, and β represents an angle formed by a reference axis, which is obtained by perpendicularly projecting the c axis of the hexagonal Group-III nitride semiconductor crystal to the crystal face cut out by the wire, and a cutting direction.

A method cuts slices from workpieces using a wire saw having a wire array, which is tensioned in a plane between two wire guide rollers supported between fixed and floating bearings and having a chamber and a shell. The workpiece is fed through the wire array along a feed direction perpendicular to a workpiece axis, while simultaneously changing the shells' lengths by adjusting a temperature of the chambers with a first cooling fluid in accordance with a first correction profile specifying a change in the shells' lengths based on the depth of cut. The floating bearings are simultaneously axially moved by adjusting a temperature of the fixed bearings with a second cooling fluid in accordance with a second correction profile, which specifies a travel of the floating bearings based on the depth of cut. The first correction profile and the second correction profile are opposed to a shape deviation.