Abstract: A method of processing a bonded wafer formed by bonding a first wafer and a second wafer to each other via a bonding layer includes a coordinate generating step of generating coordinates of an undersurface position of the first wafer, the undersurface position being to be irradiated with laser beams, such that an end position of a crack extending from modified layers formed within the first wafer is located at an outer circumference of the bonding layer, and a modified layer forming step of forming a plurality of modified layers in a ring shape by irradiating the coordinates generated in the coordinate generating step with the laser beams of a wavelength transmissible through the first wafer.

Abstract: A processing method of a bonded wafer includes generating coordinates of an outermost circumference of a joining layer, forming a plurality of modified layers by positioning focal points of laser beams inside a first wafer, from a back surface of the first wafer, holding a second wafer side on a chuck table and grinding the back surface of the first wafer to thin the first wafer. The plurality of focal points of the laser beams are set in a form of descending stairs to reach the lowermost focal point from the uppermost focal point so as to gradually get closer to the joining layer from an inner side toward an outer side in a radial direction of the first wafer. A crack that extends from the modified layer formed by the lowermost focal point reaches the coordinates of the outermost circumference of the joining layer.

Abstract: A wafer processing method includes bonding one surface of a first wafer to a second wafer, the first wafer having a device region on the one surface, a peripheral surplus region, and a chamfered peripheral edge; forming an annular modified layer along a boundary of the device region and the peripheral surplus region by applying a laser beam to the first wafer from the other surface of the first wafer with a focal point of the laser beam placed at the boundary; after forming the modified layer, grinding the first wafer from the other surface to thin the first wafer to a finished thickness; and exerting an external force on the peripheral surplus region that is close to the peripheral edge with respect to a region in which the modified layer is formed, to thereby facilitate the separation of the peripheral surplus region.

Abstract: A method of processing a wafer includes forming a bonded wafer assembly by bonding one of opposite surfaces of a first wafer to a second wafer, the first wafer having a device region and an outer circumferential excessive region, applying a laser beam to the first wafer while positioning a focused spot of the laser beam radially inwardly from the outer circumferential edge of the first wafer, on an inclined plane that is progressively closer to the one of the opposite surfaces of the first wafer toward the outer circumferential edge, thereby forming a separation layer shaped as a side surface of a truncated cone, grinding the first wafer from the other one of the opposite surfaces thereof to thin down the first wafer to a predetermined thickness, and detecting whether or not the outer circumferential excessive region has been removed from the first wafer.

Abstract: A method for processing a bonded wafer includes forming a plurality of modified layers in a form of rings through positioning focal points of laser beams with a wavelength having transmissibility with respect to a first wafer inside the first wafer, from which a chamfered part and a notch are to be removed, from a back surface of the first wafer and executing irradiation, holding a second wafer side on a chuck table, and grinding the back surface of the first wafer to thin the first wafer. In forming the modified layer, the focal points of the laser beams are set in such a manner as to gradually get closer to a joining layer from an inner side toward an outer side of the first wafer in a radial direction to thereby form the modified layers as to widen toward the lower side.

Abstract: An inspection method of a workpiece includes a separation layer forming step of forming a separation layer composed of a modified layer parallel to an upper surface and cracks that extend from the modified layer inside the workpiece, an irradiation step of irradiating the whole of the upper surface of the workpiece in which the separation layer has been formed with light with such a wavelength as to be transmitted through the workpiece and reflect at the crack of the separation layer after the separation layer forming step is executed, a light reception step of receiving reflected light resulting from the irradiation in the irradiation step and reflection by the crack, and a determination step of determining the state of the separation layer on the basis of the intensity of the reflected light received in the light reception step.

Abstract: A processing method of a bonded wafer includes forming a plurality of modified layers in a form of rings through positioning focal points of laser beams with a wavelength having transmissibility with respect to a first wafer inside the first wafer, from which a chamfered part is to be removed, from a back surface of the first wafer and executing irradiation, holding a second wafer side on a chuck table, and grinding the back surface of the first wafer to thin the first wafer. In the forming the modified layers, the focal points of the laser beams are set in such a manner as to gradually get closer to a joining layer in a direction from an inner side of the first wafer toward an outer side thereof, so that the plurality of ring-shaped modified layers are formed in a form of descending stairs.

Abstract: A method of manufacturing a wafer includes an entire plane processing step and a separating step. The entire plane processing step repeats a separation initiating point forming step of, while positioning a focused spot of a laser beam within an ingot, moving the focused spot and the ingot relatively to each other along a predetermined processing feed direction, thereby forming in the ingot separation initiating points including modified layers in a plane parallel to a first surface of the ingot and cracks developed from the modified layers, and an indexing feed step of indexing-feeding the focused spot of the laser beam relatively to the ingot in a direction perpendicular to the processing feed direction. The separating step separates a wafer from the ingot along the separation initiating points.

Abstract: The application of laser beams to at least two of a plurality of regions extending along a predetermined direction and the changing of at least two regions to which the laser beams are to be applied are alternately repeated to form peel-off layers in the ingot that include a plurality of modified portions positioned at a predetermined depth from the surface of the workpiece and cracks developed from the respective modified portions. The laser beams for forming the peel-off layers in the workpiece are thus simultaneously applied to the at least two of the regions. Therefore, it is possible to increase the throughput compared with a process in which the laser beams are applied successively to the regions.

Abstract: A manufacturing method of a single crystal silicon substrate includes a peeling layer forming step of forming, inside a workpiece, peeling layers that include modified portions and cracks propagating from the modified portions, and a separation step of separating the substrate from the workpiece using the peeling layers as starting points. The peeling layer forming step has a first processing step of forming some of the modified portions in first regions that each extend along a first direction and are separated from one another in a second direction orthogonal to the first direction, and a second processing step of forming the remaining part of the modified portions and the cracks in second regions that each extend along the first direction and that are separated from one another in the second direction.

Abstract: A preliminary processing step of forming modified parts in an outer circumferential region of a workpiece is executed prior to a main processing step of forming modified parts and cracks in each of plural linear regions included in the workpiece. This can promote extension of the cracks in the outer circumferential region of the workpiece in the main processing step. As a result, splitting-off of a substrate from the workpiece in a splitting-off step becomes easy. In addition, the probability of occurrence of large chipping in the outer circumferential region of the workpiece in this splitting-off can be reduced.

Abstract: There is provided a manufacturing method of a single-crystal silicon substrate by which the substrate is manufactured from a workpiece composed of single-crystal silicon manufactured in such a manner that a specific crystal plane included in the crystal planes {100} is exposed in each of a front surface and a back surface. The manufacturing method includes a separation layer forming step of forming separation layers including modified parts and cracks that extend from the modified parts inside the workpiece and a splitting-off step of splitting off the substrate from the workpiece with use of the separation layers as the point of origin after the separation layer forming step is executed. In the separation layer forming step, the separation layers are formed inside the workpiece composed of the single-crystal silicon by using a laser beam with such a wavelength as to be transmitted through the single-crystal silicon.

Abstract: A peeling layer is formed in a workpiece in a state in which a laser beam is condensed so as to have a larger length along an indexing feed direction than a length along a processing feed direction. In this case, cracks included in the peeling layer extend along the indexing feed direction easily. It is consequently possible to increase a relative moving distance (index) between a place where the laser beam is condensed and the workpiece in an indexing feed step. As a result, it is possible to improve the throughput of a substrate manufacturing method using the laser beam.

Abstract: A processing method for processing a single-crystal silicon wafer that has a first surface and a second surface formed in such a manner that a specific crystal plane included in a crystal plane {100} is exposed in each of the first and second surfaces and has devices formed in the respective regions marked out by planned dividing lines in the first surface. The method includes forming dividing origins along each planned dividing line, forming a separation layer along the crystal plane of the second surface through relatively moving a focal point and the wafer along a first direction that is parallel to the crystal plane of the second surface and in which an acute angle formed between the first direction and the crystal orientation <100> is equal to or smaller than 5°, and separating the wafer into a first-surface-side wafer including devices and a second-surface-side wafer including no devices.

Abstract: A peel-off layer is finally formed in an area, i.e., a first inner area or a second inner area, in a workpiece that is closer to the center of the workpiece among a plurality of areas. The workpiece has a cylindrical shape, so that the second inner area is wider than the other areas, e.g., the second outer area, in which the peel-off layers are formed. Consequently, when the peel-off layer is finally formed in the second inner area, the internal stresses in the workpiece are dispersed in a wider range than when the peel-off layer is finally formed in the second outer area. Thus, large cracks thicknesswise of the workpiece are prevented from being developed from modified regions contained in the peel-off layer. Therefore, the amount of workpiece material to be disposed of in subsequent steps is reduced, resulting in increased manufacturing productivity.

Abstract: After peel-off layers have been formed in a workpiece of monocrystalline silicon such as an ingot, a bare wafer, or a device wafer with use of a laser beam having a wavelength transmittable through monocrystalline silicon, a substrate is separated from the workpiece along the peel-off layers acting as separation initiating points. The process results in increased productivity for the manufacture of substrates, compared with a process of manufacturing substrates from a workpiece with use of a wire saw.

Abstract: A substrate manufacturing method of manufacturing a substrate from a workpiece is disclosed. A laser beam is first split and condensed to form a plurality of focal points aligned side by side along a first direction, and with the focal points positioned inside the workpiece, the focal points and the workpiece are moved relative to each other along a second direction orthogonal to the first direction such that a separation layer is formed. A region of the focal points and the workpiece are then moved relative to each other along the first direction. These relative movements are alternately and repeatedly performed. The splitting and condensation of the laser beam are performed such that a volume expansion of the workpiece associated with the formation of the modified regions is relatively small in the vicinity of at least one focal point formed on a center side.

Abstract: A monocrystalline silicon wafer fabricated such that a particular crystal plane, e.g., a crystal plane (100), included in crystal planes {100} is exposed on each of face and reverse sides of the monocrystalline silicon wafer is irradiated with a laser beam along a first direction parallel to the particular crystal plane and inclined to a particular crystal orientation, e.g., a crystal orientation [010], included in crystal orientations <100> at an angle of 5° or less, thereby forming a peel-off layer that functions as separation initiating points between a part of the monocrystalline silicon wafer that belongs to the face side thereof and a part of the monocrystalline silicon wafer that belongs to the reverse side thereof.

Abstract: After separation layers are formed inside a single-crystal silicon ingot, a single-crystal silicon substrate is split off from the single-crystal silicon ingot with use of these separation layers as the point of origin. This can improve the productivity of the single-crystal silicon substrate compared with the case of manufacturing the single-crystal silicon substrate from the single-crystal silicon ingot by a wire saw.

Abstract: A first peel-off layer extending along a side surface of a truncated cone that has a first bottom surface positioned near a face side of a wafer and a second bottom surface positioned within the wafer and smaller in diameter than the first bottom surface, and a second peel-off layer extending along the second bottom surface of the truncated cone are formed in the wafer. Then, external forces are exerted on the wafer thicknesswise of the wafer, thereby dividing the wafer along the first peel-off layer and the second peel-off layer that function as division initiating points.