A substrate dividing method includes preparing a substrate that is formed with division start points along streets and that has a protective sheet attached to a surface on one side thereof and rolling a roller on a surface on the other side of the substrate, to attach an expanding tape. Next, suction by a holding table is cancelled, and, in a state in which a slight gap is formed between a holding surface of the holding table and the protective sheet, the roller is brought into contact with the expanding tape and rolled, thereby extending cracks extending from the division start points while causing the substrate to sink into the gap through the protective sheet with the division start points as starting points, and the expanding tape is expanded to widen the chip intervals with the division start points as starting points.

A substrate dividing method includes preparing a substrate that is formed with division start points along streets and that has a protective sheet attached to a surface on one side thereof and rolling a roller on a surface on the other side of the substrate, to attach an expanding tape. Next, suction by a holding table is cancelled, and, in a state in which a slight gap is formed between a holding surface of the holding table and the protective sheet, the roller is brought into contact with the expanding tape and rolled, thereby extending cracks extending from the division start points while causing the substrate to sink into the gap through the protective sheet with the division start points as starting points, and the expanding tape is expanded to widen the chip intervals with the division start points as starting points.

A method of manufacturing a gallium nitride substrate includes preparation of a gallium nitride wafer, formation of a transformation layer, and formation of the gallium nitride substrate. The gallium nitride has a first main surface and a second main surface on a side opposite from the first main surface. The gallium nitride wafer is made of a hexagonal crystal, and each of the first main surface and the second main surface is a {1-100} m-plane of the hexagonal crystal. The transformation layer is formed along a planar direction of the gallium nitride wafer by emitting a laser beam into the gallium nitride wafer. The gallium nitride substrate is formed from the gallium nitride wafer by dividing the gallium nitride wafer at the transformation layer. In the formation of the transformation layer, the laser beam is emitted to form an irradiation mark for forming the transformation layer.

A method of manufacturing a gallium nitride substrate includes preparation of a gallium nitride wafer, formation of a transformation layer, and formation of the gallium nitride substrate. The gallium nitride has a first main surface and a second main surface on a side opposite from the first main surface. The gallium nitride wafer is made of a hexagonal crystal, and each of the first main surface and the second main surface is a {1-100} m-plane of the hexagonal crystal. The transformation layer is formed along a planar direction of the gallium nitride wafer by emitting a laser beam into the gallium nitride wafer. The gallium nitride substrate is formed from the gallium nitride wafer by dividing the gallium nitride wafer at the transformation layer. In the formation of the transformation layer, the laser beam is emitted to form an irradiation mark for forming the transformation layer.

A chip package includes a semiconductor substrate, a conductive pad, an isolation layer, and a redistribution layer. The semiconductor substrate has a first surface, a second surface facing away from the first surface, a through hole through the first and second surfaces, and a recess in the first surface. The conductive pad is located on the second surface of the semiconductor substrate and in the through hole. The isolation layer is located on the second surface of the semiconductor substrate and surrounds the conductive pad. The redistribution layer is located on the first surface of the semiconductor substrate, and extends into the recess, and extends onto the conductive pad in the through hole.

A chip package includes a semiconductor substrate, a conductive pad, an isolation layer, and a redistribution layer. The semiconductor substrate has a first surface, a second surface facing away from the first surface, a through hole through the first and second surfaces, and a recess in the first surface. The conductive pad is located on the second surface of the semiconductor substrate and in the through hole. The isolation layer is located on the second surface of the semiconductor substrate and surrounds the conductive pad. The redistribution layer is located on the first surface of the semiconductor substrate, and extends into the recess, and extends onto the conductive pad in the through hole.

A laser processing device includes: a light source configured to output laser light; a space light modulator for modulating the laser light output from the light source in accordance with a modulation pattern and outputting the modulated laser light; a converging lens for converging the laser light output from the space light modulator to an object, and forming a converging spot on the object; a movement unit for relatively moving the converging spot with respect to the object; and a control unit for relatively moving, while setting a position of the converging spot in a Z direction intersecting with an incident surface of the laser light on the object at a first Z position, the converging spot along a line extended in an X direction along the incident surface by controlling at least the space light modulator and the movement unit.

A method for manufacturing a semiconductor device, includes: applying a laser beam to a plane extending at a predetermined depth in a semiconductor substrate from a second main surface side of the semiconductor substrate opposite to a first main surface side on which a device structure including a channel is formed; and peeling off a device layer including the device structure from the semiconductor substrate along the plane applied with the laser beam. In the applying of the laser beam, the laser beam is applied so that a power density is lower in a region corresponding to the channel in a thickness direction of the semiconductor substrate than in the other region, in the plane extending at the predetermined depth in the semiconductor substrate.

A method for manufacturing a semiconductor device, includes: applying a laser beam to a plane extending at a predetermined depth in a semiconductor substrate from a second main surface side of the semiconductor substrate opposite to a first main surface side on which a device structure including a channel is formed; and peeling off a device layer including the device structure from the semiconductor substrate along the plane applied with the laser beam. In the applying of the laser beam, the laser beam is applied so that a power density is lower in a region corresponding to the channel in a thickness direction of the semiconductor substrate than in the other region, in the plane extending at the predetermined depth in the semiconductor substrate.

A semiconductor device includes: a semiconductor chip having a bottom surface having a first area and a first side surface; and an electrode provided below the semiconductor chip, the electrode having a first top surface and a second side surface, and the electrode containing an electrically conductive material, wherein the first top surface has a second area larger than the first area, and at least a part of the first top surface is in contact with the bottom surface.