Abstract: A wafer is produced from a compound single crystal ingot having end surface. A separation plane is formed by setting the focal point of a laser beam inside the ingot at a predetermined depth from the end surface. The depth corresponds to the thickness of the wafer to be produced. The laser beam is applied to the end surface to form a modified layer parallel to the end surface and cracks extending from the modified layer, thus forming the separation plane. The ingot has first atoms having a larger atomic weight and second atoms having a smaller atomic weight, and the end surface of the ingot is set as a polar plane where the second atoms are arranged in forming the separation plane. After producing the wafer from the ingot, the first end surface is ground to be flattened.

Abstract: Disclosed herein is an SiC wafer producing method for producing an SiC wafer from a single crystal SiC ingot. The SiC wafer producing method includes a wafer producing step of separating a part of the ingot along a separation layer as an interface. The wafer producing step includes the steps of immersing the ingot in a liquid and applying the ultrasonic wave from an ultrasonic vibrator through the liquid to the ingot, the ultrasonic wave having a frequency greater than or equal to a critical frequency close to the natural frequency of the ingot.

Abstract: A method for producing a wafer from an ingot of single crystal SiC includes an end surface planarizing step of planarizing an end surface of the ingot, a separation layer forming step of setting a focal point of a laser beam having a transmission wavelength to single crystal SiC inside the ingot at a predetermined depth from the end surface of the ingot, the predetermined depth corresponding to the thickness of the wafer to be produced, and next applying the laser beam to the ingot to thereby form a separation layer for separating the wafer from the ingot, a hard plate providing step of providing a hard plate through an adhesive on the end surface of the ingot in which the separation layer has been formed, and a separating step of separating the wafer with the hard plate from the ingot along the separation layer.

Abstract: Disclosed herein is a laser processing apparatus for forming a separation layer inside an ingot by applying a laser beam to an end surface of the ingot in the condition where the focal point of the laser beam is set inside the ingot, the laser beam having a transmission wavelength to the ingot. The laser processing apparatus includes a holding unit for holding the ingot, a moving unit for moving the holding unit in a direction parallel to the end surface of the ingot held by the holding unit, a laser beam applying unit for applying the laser beam to the ingot held by the holding unit, an imaging unit for detecting the position of the ingot in the direction parallel to the end surface of the ingot, and a height detecting unit for detecting the height of the end surface of the ingot held by the holding unit.

Abstract: A shaft seal device is fixed to a container that separates a high-pressure fluid and a low-pressure fluid from each other, and seals a shaft-penetrated portion of the container through which a rotational shaft extends. This shaft seal device includes: a seal casing having a through-hole through which the rotational shaft extends, the seal casing having a seal chamber which communicates with the through-hole and into which the high-pressure fluid flows; and a disk-shaped seal body which is housed in the seal chamber, the seal body being rotatable together with the rotational shaft and having an annular surface perpendicular to an axis of the rotational shaft. An inner surface of the seal casing, which faces the annular surface of the seal body and defines the seal chamber, is a flat surface perpendicular to the axis of the rotational shaft.

Abstract: A hexagonal single crystal wafer is produced from a hexagonal single crystal ingot. The depth of the focal point of a laser beam is gradually changed from a shallow position not reaching the depth corresponding to the desired thickness of the wafer to a deep position corresponding to the desired thickness of the wafer in such a manner that a parabola is described by the path of the focal point. When the spot area of the laser beam on the upper surface of the ingot becomes a predetermined maximum value, the deep position of the focal point is maintained.

Abstract: A SiC wafer producing method produces an SiC wafer from a single crystal SiC ingot. The method includes a separation layer forming step of setting a focal point of a pulsed laser beam having a transmission wavelength to single crystal SiC inside the ingot at a predetermined depth from an end surface of the ingot, the predetermined depth corresponding to the thickness of the wafer to be produced, and next applying the pulsed laser beam to the ingot, thereby forming a plurality of modified portions on a c-plane present in the ingot at the predetermined depth and also forming cracks isotropically on the c-plane so as to extend from each modified portion, each modified portion being a region where SiC has been decomposed into Si and C, the modified portions and the cracks constituting a separation layer along which the wafer is to be separated from the ingot.

Abstract: An SiC wafer producing method includes setting a focal point of a pulsed laser beam to a single crystal SiC inside an ingot at a predetermined depth from an end surface of the ingot, the predetermined depth corresponding to the thickness of the wafer to be produced. The pulsed laser beam is applied to the ingot, thereby forming a small circular modified portion on a c-plane present in the ingot at the predetermined depth, in which the modified portion is a region where SiC has been decomposed into Si and C. A separation layer is formed for separating the wafer from the ingot, the separation layer being composed of a plurality of continuous modified portions and a plurality of cracks isotropically formed on the c-plane so as to extend from each modified portion.

Abstract: A wafer having an off angle ? is produced from a hexagonal single crystal ingot having an upper surface, a c-plane exposed to the upper surface, and a c-axis perpendicular to the c-plane. The ingot is supported by a wedge member having a wedge angle ? equal to the off angle ?, thereby inclining the upper surface of the ingot by the off angle ? with respect to a horizontal plane. A modified layer is formed by setting the focal point of a laser beam inside the ingot and next applying it to the upper surface, thereby linearly forming a modified layer inside the ingot and cracks extending from the modified layer along the c-plane. The focal point is moved in the second direction to index the focal point by a predetermined amount.

Abstract: An SiC wafer is generated from an SiC ingot by a peel-off plane generating step for generating a peel-off plane by forming a separation layer made up of a modified layer, and cracks extending from the modified layer along a c-plane, a plurality of times by indexing-feeding a focused point of a pulsed laser beam and the SiC ingot relative to each other in a direction in which an off-angle is formed, thereby forming a plurality of separation layers to generate the peel-off plane. The peel-off plane generating step includes relatively moving the focused point from an end to an opposite end of the SiC ingot in a forward stroke and relatively moving the focused point from the opposite end to the end of the SiC ingot in a backward stroke to trace back the separation layer that has already been formed in the forward stroke.

Abstract: A thin plate is separated from an SiC substrate having a first surface, an opposite second surface, a c-axis extending from the first surface to the second surface, and a c-plane perpendicular to the c-axis. The thin plate is formed by epitaxial growth on the first surface of the SiC substrate. The plate is separated by a separation start point forming step of setting the focal point of a laser beam near the first surface of the SiC substrate from the second surface, and applying the laser beam to the second surface to form a modified layer parallel to the first surface and cracks extending from the modified layer along the c-plane, thus forming a separation start point. An external force is applied to the SiC substrate to separate the thin plate from the SiC substrate at the separation start point.

Abstract: A SiC wafer is produced from a single crystal SiC ingot. A modified layer is formed by setting a focal point of a pulsed laser beam inside the ingot at a predetermined depth from the upper surface of the ingot, the predetermined depth corresponding to the thickness of the wafer to be produced. The pulsed laser beam is applied to the ingot while moving the ingot in a first direction perpendicular to a second direction where an off angle is formed, thereby forming a modified layer in the first direction inside the ingot and cracks propagating from the modified layer along a c-plane. A separation surface is formed by indexing the ingot in the second direction and applying the laser beam plural times to thereby form a separation surface inside the ingot. Part of the ingot is separated along the separation surface to thereby produce the wafer.

Abstract: A hexagonal single crystal wafer is produced from a hexagonal single crystal ingot. A separation start point is formed by setting a focal point of a laser beam inside the ingot at a predetermined depth from the upper surface of the ingot, which depth corresponds to a thickness of the wafer to be produced. The laser beam is applied to the upper surface of the ingot while relatively moving the focal point and the ingot to thereby form a modified layer parallel to the upper surface of the ingot and form cracks extending from the modified layer along a c-plane, thus forming a separation start point. The wafer is separated by immersing the ingot in water and then applying ultrasonic vibration to the ingot, thereby separating a plate-shaped member having a thickness corresponding to the thickness of the wafer from the ingot.

Abstract: An SiC wafer is generated from an SiC ingot by a peel-off plane generating step for generating a peel-off plane by forming a separation layer made up of a modified layer, and cracks extending from the modified layer along a c-plane, a plurality of times by indexing-feeding a focused point of a pulsed laser beam and the SiC ingot relative to each other in a direction in which an off-angle is formed, thereby forming a plurality of separation layers to generate the peel-off plane. The peel-off plane generating step includes relatively moving the focused point from an end to an opposite end of the SiC ingot in a forward stroke and relatively moving the focused point from the opposite end to the end of the SiC ingot in a backward stroke to trace back the separation layer that has already been formed in the forward stroke.

Abstract: A wafer formed from an SiC substrate having a first surface and a second surface is divided into individual device chips. A division start point formed by a laser has a depth corresponding to the finished thickness of each device chip along each division line formed on the first surface. The focal point of the laser beam is set inside the SiC substrate at a predetermined depth from the second surface, and the laser beam is applied to the second surface while relatively moving the focal point and the SiC substrate to thereby form a modified layer parallel to the first surface and cracks extending from the modified layer along a c-plane, thus forming a separation start point. An external force is applied to the wafer, thereby separating the wafer into a first wafer having the first surface and a second wafer having the second surface.

Abstract: An SiC wafer is produced from a single crystal SiC ingot by a method that includes forming a plurality of breakable layers constituting a separation surface in the SiC ingot, each breakable layer including a modified layer and cracks extending from the modified layer along a c-plane, and separating part of the SiC ingot along the separation surface as an interface to thereby produce the SiC wafer. In forming the separation surface, the energy density of a pulsed laser beam is set to an energy density not causing the formation of an upper damage layer above the breakable layer previously formed due to the reflection of the pulsed laser beam from the breakable layer and not causing the formation of a lower damage layer below the breakable layer previously formed due to the transmission of the pulsed laser beam through the breakable layer.

Abstract: A hexagonal single crystal wafer is produced from a hexagonal single crystal ingot. The wafer producing method includes a separation start point forming step of setting the focal point of a laser beam to the inside of the ingot at a predetermined depth from the upper surface of the ingot, which depth corresponds to the thickness of the wafer to be produced, and next applying the laser beam to the upper surface of the ingot while relatively moving the focal point and the ingot to thereby form a modified layer parallel to the upper surface of the ingot and cracks extending from the modified layer, thus forming a separation start point. A plate-shaped member having a thickness corresponding to the thickness of the wafer is separated from the ingot at the separation start point after performing the separation start point forming step, thus producing the wafer from the ingot.

Abstract: Disclosed herein is an SiC ingot slicing method including: an initial separation layer formation step for scanning a focal point of a laser beam parallel to an end face of the SiC ingot along a scheduled separation plane, and forming a separation layer at a position at a distance from the end face; a repetition step for sequentially moving, after the initial separation layer formation step, the focal point by the distance equal to the thickness of an SiC plate from the separation layer toward the end face, scanning the focal point parallel to the end face, repeating the formation of the separation layer, and forming the plurality of separation layers; and a separation step for applying an external force to the plurality of separation layers formed by the repetition step, peeling off the SiC plates starting from the separation layers, and acquiring the plurality of SiC plates.

Abstract: A SiC wafer is produced from an SiC ingot having an end surface by setting the focal point of a laser beam at a predetermined depth from the end surface. The depth corresponds to the thickness of the SiC wafer to be produced. The laser beam is applied to the end surface of the SiC ingot while relatively moving the focal point and the SiC ingot to thereby form a modified layer parallel to the end surface and cracks extending from the modified layer, thus forming a separation start point. The separation start point is formed by setting the numerical aperture of a focusing lens to form the focal point to 0.45 to 0.9 and substantially setting the M2 factor of the laser beam between 5 and 50 to thereby set the diameter of the focal point to 15 to 150 ?m.

Abstract: A sound deadening device has an introducing and damping section. The introducing and damping section includes an introduction section that introduces fluid, an expansion chamber, and a lead-out section. The expansion chamber is communicated with the introduction section, has a flow passage cross-section larger than a flow passage cross-section of the introduction section, and has protrusions along a travelling direction of a sound wave, resonance of the sound wave being to be suppressed. The lead-out section is communicated with the expansion chamber, has a flow passage cross-section smaller than that of the expansion chamber, and leads out the fluid in a direction different from an introduction direction of the fluid. Accordingly, it is possible to weaken the resonance of the sound wave, suppress rise of inner sound pressure of the sound deadening device, and prevent reduction in a sound deadening effect.