Abstract: Provided is a laser processing apparatus configured to irradiate a substrate including a first main surface and a second main surface opposite to the first main surface with processing laser light. The laser processing apparatus includes: a processing irradiation unit configured to irradiate the substrate with the processing laser light from the second main surface side; an observation irradiation unit configured to irradiate the substrate with observation transmission light from the second main surface side; an imaging element configured to image the observation transmission light from the substrate; and a controller configured to execute a processing process of irradiating the substrate with the processing laser light by controlling the processing irradiation unit, and a characteristic acquisition process of irradiating the substrate with the observation transmission light, imaging the observation transmission light from the substrate.

Abstract: A laser machining method performed by a laser machining device includes: a first step of flattening an irradiation surface through laser annealing by irradiating a surface or a back surface of an object with a laser beam, the object including a functional element layer on a surface side; and a second step of forming a modified layer inside the object by irradiating the irradiation surface, which is flattened in the first step, with a laser beam. A pulse pitch of the laser beam is shorter than a pulse pitch of the laser beam.

Abstract: A laser processing apparatus includes a support unit that supports a wafer including a plurality of functional elements disposed adjacent to each other via a street, an irradiation unit that irradiates the street with laser light, and a control unit that controls the irradiation unit based on information about the streets so that a first region and a second region of the street are simultaneously irradiated with the laser light, and a power of the laser light for removing a surface layer of the street in the first region is higher than a power for removing the surface layer of the street in the first region. The information about the street includes information that a processing threshold value indicating a difficulty of laser processing in the first region is lower than a processing threshold value in the second region.

Abstract: A laser processing method includes: a first step of preparing a wafer including a plurality of functional elements disposed to be adjacent to each other via a street; and a second step of, after the first step, irradiating the street with laser light based on information regarding the street such that a surface layer of the street is removed in a first region of the street and the surface layer remains in a second region of the street. The information regarding the street includes information indicating that, when a modified region is formed in the wafer along a line passing through the street, a fracture extending from the modified region does not reach the street along the line in the first region, and reaches the street along the line in the second region.

Abstract: A laser processing method includes a first step of preparing a wafer including a plurality of functional elements disposed to be adjacent to each other via a street, a second step of, after the first step, forming a modified region in the wafer along a line passing through the street, and a third step of, after the second step, irradiating the street with laser light such that a surface layer of the street is removed, and a fracture extending from the modified region reaches a bottom surface of a recess formed by removing the surface layer, along the line.

Abstract: A laser processing device includes: a support table; a laser light source; a converging optical system; an imaging unit configured to image a front surface of an object; a candidate line setting unit configured to set a plurality of candidate lines; an operation controller configured to control operation of at least one of the support table, the laser light source, and the converging optical system such that a modified region is formed inside the object along each of the plurality of candidate lines, and a crack reaches the front surface of the object from the modified region; and a reference line setting unit configured to set a reference line determined as a line indicating a crystal orientation of the object on the basis of an image of the crack.

Abstract: The object to be processed cutting method includes: a crystal orientation identifying step of identifying a crystal orientation of the substrate; a line to cut setting step of setting, for the object to be processed, a line to cut passing through a street region formed between adjacent functional devices, after the crystal orientation identifying step; and a cutting step of cutting the object to be processed along the line to cut, after the line to cut setting step. In the line to cut setting step, in a case where an extending direction of the street region does not match the crystal orientation, the line to cut parallel to the crystal orientation and inclined with respect to the extending direction of the street region, is set for the object to be processed.

Abstract: A laser processing device includes: a support table configured to support an object to be processed; a laser light source configured to emit laser light; a converging optical system configured to converge the laser light at the object; an imaging unit configured to image a front surface of the object; a candidate line setting unit configured to set a plurality of candidate lines; an operation controller configured to control operation of at least one of the support table, the laser light source, and the converging optical system such that a modified region is formed inside the substrate along each of the plurality of candidate lines, and a crack reaches the front surface of the object from the modified region; and a reference line setting unit configured to set a reference line determined as a line indicating a crystal orientation of the substrate on the basis of an image of the crack.

Abstract: The object to be processed cutting method includes: a crystal orientation identifying step of identifying a crystal orientation of the substrate; a line to cut setting step of setting, for the object to be processed, a line to cut passing through a street region formed between adjacent functional devices, after the crystal orientation identifying step; and a cutting step of cutting the object to be processed along the line to cut, after the line to cut setting step. In the line to cut setting step, in a case where an extending direction of the street region does not match the crystal orientation, the line to cut parallel to the crystal orientation and inclined with respect to the extending direction of the street region, is set for the object to be processed.