A silicon carbide ingot includes an end surface and an end surface opposite to the end surface. In the silicon carbide ingot, the end surface and the end surface face each other in a growth direction, and a gradient of a nitrogen concentration in the growth direction is not less than 110.sup.16 cm.sup.4 and not more than 110.sup.18 cm.sup.4.

A marked abrasive wire including, on the cylindrical outer face thereof and between abrasive particles, a mark that is deformed as a function of the twisting of the abrasive wire, this mark extending longitudinally over at least 50% of the total length of the abrasive wire and having a reflectance Rm at a wavelength m,during the displacement of the wire and with the aid of a sensor sensitive to the reflectance of the outer face of the abrasive wire, the reading of at least one characteristic of the current shape of the mark that varies as a function of the twisting of the abrasive wire, andthe estimation of the twisting of the abrasive wire from the observed characteristic of the current shape of the mark and from a known value of this characteristic corresponding to a known twisting of the abrasive wire.

Methods for controlling the surface profiles of wafers sliced from an ingot with a wire saw include measuring an amount of displacement of a sidewall of a frame of the wire saw. The sidewall is connected to a bearing of a wire guide supporting a wire web in the wire saw. Based on the measured amount of displacement of the sidewall, a pressure profile for adjusting a position of the sidewall is determined by a computing device. Pressure is applied to the sidewall using a displacement device according to the determined pressure profile to control the position of the sidewall.

The wire saw device includes at least one wire, which is provided tightly to be capable of travelling in a direction crossing a workpiece to be cut, a workpiece holder, which is configured to hold the workpiece and to move the workpiece relative to the wire, slurry suppliers, which are configured to supply slurry to cut the workpiece from an upstream side in a travelling direction of the wire, and slurry collectors, which are configured to collect the slurry scattered due to contact with the workpiece. The slurry collector is configured to be movable in conjunction with the workpiece in the state where the slurry collector is disposed adjacent to the workpiece and also configured to be retractable with respect to the workpiece to be prevented from contacting the wire.

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.

The present disclosure relates to an ingot slicing apparatus, including an ingot moving apparatus provided to be movable vertically and supply an ingot, a wire rotating apparatus provided to be movable horizontally to slice the ingot, a slurry supply unit provided to supply slurry to the slicing apparatus, and an air supply unit provided to supply air to the slicing apparatus and to adjust a supplying amount of the slurry supplied to the slicing apparatus.

A metal wire containing tungsten is provided. A tungsten content of the metal wire is at least 90 wt %. A tensile strength of the metal wire is at least 4000 MPa. An elastic modulus of the metal wire is at least 350 GPa and at most 450 GPa. A diameter of the metal wire is at most 60 m. An average crystal grain size of the metal wire in a cross-section orthogonal to an axis of the metal wire is at most 0.20 m.

In an ingot cutting apparatus that cuts an ingot using a plurality of stretched wires, load sensors are provided on the new wire side and the old wire side of the ingot, and loads applied to the new wire side and the old wire side of the ingot are measured using the load sensors on the new wire side and the old wire side. When measuring the loads, for example, the center of moment about the X-axis that is the running direction of the wire is calculated. When the deviation from the center of gravity of the ingot is greater than or equal to a reference value, notification for replacement of the wire, control of the conveying speed of the wire, control of the pressing speed of the ingot, and so forth are performed through a control unit.

Embodiments of the disclosure provide a method and device for providing a wire breakage warning. The method includes: obtaining a plurality of process values when a crystal ingot cutting machine uses a cutting wire to cut a crystal ingot; dividing the process values into N groups, and determining a statistical property of each of the groups; identifying outlier values in the process values based on the statistical property of each of the groups, or determining a statistical property variation corresponding to each of the groups based on the statistical property of each of the groups; and in response to determining that the outlier values in the process values meet a first warning condition, or the statistical property variation corresponding to each of the groups meets a second warning condition, providing a wire breakage warning associated with the cutting wire.

Method for slicing a workpiece, including measuring a crystal axis orientation while holding a workpiece with a workpiece holder, setting the workpiece holder to a wire saw in such a manner that the measured crystal axis orientation is maintained, then adjusting a sliced plane orientation, pressing the workpiece against a wire row to slice the workpiece; the workpiece holder includes a portion slidable while holding the workpiece and a portion for fixing the slide portion, after measuring the crystal axis orientation, sliding the slide portion to move to the workpiece holder center in a manner that the measured crystal axis orientation is maintained, fixing the slide portion, setting the workpiece holder to the wire saw, then adjusting the sliced plane orientation, and slicing the workpiece. This enables an orientation measurement without limitation of distance between an orientation measuring instrument and plane to be measured can inhibit warpage deterioration and workpiece breakage.