Abstract: A manufacturing method of a semiconductor device, includes: forming a gas vent recess in a first surface of a compound semiconductor substrate, which includes a plurality of device regions adjacent to the first surface, along an interface between the plurality of device regions; forming an altered layer inside the compound semiconductor substrate to extend along the first surface at a depth corresponding to a range of a depth of the gas vent recess by applying a laser beam; dividing the compound semiconductor substrate at the altered layer into a first part including the first surface and a second part including a second surface of the compound semiconductor substrate opposite to the first surface; and forming a metal film to cover a divided surface of the first part while exposing the gas vent recess.

Abstract: 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.

Abstract: A method of manufacturing a semiconductor element includes formation of a modified layer, detection of a first region, and cutting of a semiconductor wafer. In the formation of the modified layer, a laser is irradiated on the semiconductor wafer to form the modified layer extending along a surface of the semiconductor wafer inside the semiconductor wafer. The surface of the semiconductor wafer includes a peripheral portion having the first region and a second region. The first region is a region in which the modified layer is not located, and the second region is a region in which the modified layer is formed. In the cutting of the semiconductor wafer, the semiconductor wafer is cut at the modified layer starting from the second region.