Abstract: A laser oscillation mechanism of a laser beam irradiation unit has a first mode to break growing debris, a second mode to suppress generation of molten debris, and a third mode to break the growing debris and suppress generation of the molten debris. The laser oscillation mechanism includes a selecting part that selects any of the first mode, the second mode, and the third mode. The laser oscillation mechanism sets a repetition frequency with a first group being one unit in the first mode, and sets a repetition frequency with a second group being one unit in the second mode, and sets a repetition frequency with a third group being one unit in the third mode.

Abstract: A laser processing apparatus includes a laser oscillating mechanism for emitting pulsed laser beams. The laser oscillating mechanism includes a group setting section for establishing the number of pulsed laser beams to be applied to a workpiece until a time after which melted debris produced by the pulsed laser beams applied to the workpiece is solidified, and assigns the pulsed laser beams to a group, under conditions that, within a period of time which is shorter than a period of time in which the melted debris is produced, and within a period of time after which a plasma generated by the pulsed laser beam becomes extinct, a next pulsed laser beam is applied to the workpiece to sustain the plasma uninterruptedly to break growing debris, and a time interval setting section for establishing a time interval between the group and another group adjacent thereto.

Abstract: A laser beam irradiating unit of a laser processing apparatus includes a laser oscillating mechanism. The laser oscillating mechanism includes a group setting unit configured to, on a condition that a pulsed laser beam is applied at shorter time intervals than a length of time that molten debris is generated, set the number of pulsed laser beams to be applied until a time that the molten debris is solidified and set the number of pulsed laser beams as one group. A time interval setting unit is configured to set a time until heat generated by application of the pulsed laser beams of the one group is cooled, which serves as a time interval between the one group and an adjacent group, and set time intervals of the pulsed laser beams constituting the one group. The laser oscillating mechanism sets a repetition frequency with the one group as one unit.

Abstract: A method of processing a wafer includes a composite substrate forming step of joining a face side of a wafer and a surface of a support substrate to each other with a joint member interposed therebetween, a grinding step of grinding a reverse side of the wafer of the composite substrate to thin down the wafer to a finished thickness, a transfer member affixing step of affixing a transfer member to the reverse side of the wafer, a joint member breaking step of breaking the joint member by applying a laser beam having a wavelength transmittable through the support substrate and absorbable by the joint member to the composite substrate from another surface side of the support substrate, and a transferring step of peeling off the support substrate from the wafer and transferring the wafer to the transfer member.

Abstract: A laser processing apparatus includes a chuck table that holds a workpiece, a laser beam irradiation unit that irradiates the workpiece with a laser beam, and a feed mechanism that moves the chuck table and the laser beam irradiation unit relative to each other to execute processing feed. The laser beam irradiation unit includes a laser oscillation mechanism that emits a pulsed laser beam and a beam condenser that condenses the pulsed laser beam emitted by the laser oscillation mechanism and irradiates the workpiece with the pulsed laser beam. The laser oscillation mechanism has a group setting part that sets multiple pulsed laser beams into one group and a time interval setting part that sets a time interval of the pulsed laser beams that configure the one group, and sets the repetition frequency in such a manner as to regard the one group as one unit.

Abstract: An inspection apparatus for a laser oscillator includes a dimming plate that dims a laser beam immediately after the laser beam is emitted from the laser oscillator; an imaging unit that images, with a plurality of pixels, the laser beam dimmed by the dimming plate; a processing unit that processes an image captured by the imaging unit; and a display unit that displays the image processed by the processing unit. The processing unit has at least two thresholds of an inner ring and an outer ring used for partitioning the intensity of the laser beam.

Abstract: A lift-off method includes joining a transfer substrate to a face side of an optical device layer of an optical device wafer with a joining member interposed therebetween, thereby making up a composite substrate, applying a pulsed laser beam having a wavelength transmittable through the epitaxy substrate and absorbable by a buffer layer, from a reverse side of the epitaxy substrate of the optical device wafer, thereby breaking the buffer layer, and an optical device layer transferring step of peeling off the epitaxy substrate from the optical device layer and transferring the optical device layer to the transfer substrate. The optical device layer transferring step includes the step of applying a bending moment to an area of the composite substrate that includes an outer peripheral portion thereof while holding an area of the composite substrate that includes a central portion thereof.

Abstract: A laser beam irradiation unit of a laser processing apparatus includes a laser oscillator that emits a laser beam, an X-axis galvano scanner that induces the laser beam emitted by the laser oscillator in an X-axis direction, a Y-axis galvano scanner that induces the laser beam in a Y-axis direction, and a controller that controls the X-axis galvano scanner and the Y-axis galvano scanner. The controller includes a processing region storing section that stores the X-coordinate and Y-coordinate of processing regions in which a workpiece held by a chuck table is processed and an order-of-processing storing section that stores setting of the order of processing of the processing region to be processed on a forward path through irradiation with the laser beam and the processing region of a return path to be subsequently processed.

Abstract: A controller includes a spot shape storing section that stores the shape of a spot of a laser beam with which a wafer held by a chuck table is irradiated, and a processing shape storing section that stores X-coordinates and Y-coordinates on a processing shape to be formed in the wafer. When the wafer is irradiated with the spot of the laser beam, an X-axis optical scanner and a Y-axis optical scanner are controlled on the basis of the shape of the spot, and the X-coordinates and Y-coordinates on the processing shape and irradiation with the laser beam is executed so that that the contour of the shape of the spot is positioned to an X-coordinate and Y-coordinate on the processing shape, and that a tangent line to the spot and a tangent line to the processing shape at the X-coordinate and Y-coordinate correspond with each other.

Abstract: A controller of a laser processing apparatus includes a processing trajectory storage section, a thickness storage section (TSS), a limit processing depth storage section (LPDSS), a pass number storage section (PNSS), a spot overlap rate storage section, and a selecting section. The controller calculates a processing width by multiplying, by a spot diameter, a value obtained by dividing a thickness stored in the TSS by a limit value stored in the LPDSS, and calculates the number of passes of a pulsed laser beam (LB) to be applied to a section width-wise by multiplying the value obtained by dividing the thickness stored in the TSS by the limit value stored in the LPDSS by the number of passes stored in the PNSS, and multiplying a result by a number of spots determined from the spot diameter of the LB, the overlap rate of the spots, and the processing width.

Abstract: A laser processing method includes forming a first processing mark to form an origin of dividing or a dividing groove with a laser beam in a first direction, and forming a second processing mark by forming an origin of dividing or a dividing groove with the laser beam in a second direction that intersects the first direction. An unprocessed region in which the processing is not executed remains at an intersection at which the first direction and the second direction intersect each other. The method further includes processing the unprocessed region. The unprocessed region processing step forms a coupling processing mark that couples the first processing mark and the second processing mark to each other to form an origin of dividing or a dividing groove with the laser beam in a direction arising from setting an inclination with respect to the first direction or the second direction.

Abstract: A laser beam irradiation unit of a laser processing apparatus includes a laser oscillator that oscillates a laser, a Y-axis scanner that executes a high-speed scan with a laser beam emitted from the laser oscillator in a Y-axis direction, an X-axis scanner that executes processing feed of the laser beam emitted from the laser oscillator in an X-axis direction, and a beam condenser. The Y-axis scanner is selected from any of an AOD, a resonant scanner, and a polygon scanner and the X-axis scanner is selected from a galvano scanner and a resonant scanner.

Abstract: A laser processing apparatus includes a chuck table for holding a workpiece, a laser beam applying unit for applying a pulsed laser beam to the workpiece held by the chuck table while positioning spots of the pulsed laser beam on the workpiece, thereby processing the workpiece with the pulsed laser beam, and a control unit for controlling operation of the laser beam applying unit. The laser beam applying unit includes a laser oscillator for oscillating pulsed laser to emit a pulsed laser beam, a decimator for decimating pulses of the pulsed laser beam to adjust a repetitive frequency thereof, a scanner for scanning the spots of the pulsed laser beam over the workpiece at predetermined intervals, and an f? lens for focusing the pulsed laser beam.

Abstract: A laser beam irradiation unit of a laser processing apparatus includes: a laser oscillator in which a repetition frequency is set so as to oscillate a pulsed laser having a pulse width shorter than a time of electronic excitation caused by irradiating the workpiece with a laser beam and oscillate at least two pulsed lasers within the electronic excitation time; a condenser that irradiates the workpiece held on the chuck table with the pulsed laser beams oscillated by the laser oscillator; and a thinning-out unit that is disposed between the laser oscillator and the condenser and guides the pulsed laser beams necessary for processing to the condenser by thinning out and discarding pulsed laser beams in a predetermined cycle.

Abstract: There is provided a chuck table for holding a workpiece under suction. The chuck table includes a base table having a suction path to be connected to a suction source, a support member that is mounted on the base table and supports the workpiece, and a protective plate disposed so as to cover an upper surface of the support member and to protect the support member. The protective plate has a plurality of through-holes that transmits a suction force from the suction source to the workpiece.

Abstract: A comparing method includes a processing trace forming step of positioning a condenser at a reference height and a plurality of heights by moving the condenser, and forming a plurality of processing traces in one surface of a workpiece by irradiating different positions of the one surface with a laser beam according to each of the heights, a calculating step of calculating at least one of an average of widths in a plurality of predetermined directions of each of the plurality of processing traces and an area ratio of each of the plurality of processing traces to a circle of a predetermined diameter by analyzing an image of the plurality of processing traces by an image analyzing section, and a comparing step of quantitatively comparing deviations of the plurality of processing traces from a predetermined shape on the basis of at least one of the average and the area ratio.

Abstract: A laser beam irradiation unit of a laser processing apparatus includes a laser oscillator that oscillates a laser, a Y-axis scanner that executes a high-speed scan with a laser beam emitted from the laser oscillator in a Y-axis direction, an X-axis scanner that executes processing feed of the laser beam emitted from the laser oscillator in an X-axis direction, and a beam condenser. The Y-axis scanner is selected from any of an AOD, a resonant scanner, and a polygon scanner and the X-axis scanner is selected from a galvano scanner and a resonant scanner.

Abstract: An inspection apparatus for a laser oscillator includes a dimming plate that dims a laser beam immediately after the laser beam is emitted from the laser oscillator; an imaging unit that images, with a plurality of pixels, the laser beam dimmed by the dimming plate; a processing unit that processes an image captured by the imaging unit; and a display unit that displays the image processed by the processing unit. The processing unit has at least two thresholds of an inner ring and an outer ring used for partitioning the intensity of the laser beam.

Abstract: A laser processing method for a substrate with a device formed on a front surface thereof and including an electrode pad, the method including: a laser beam applying step of applying the laser beam to the back surface of the substrate to form a fine hole in the substrate at a position corresponding to the electrode pad; a detecting step of detecting first plasma light emitted from the substrate at the same time that the fine hole is formed in the substrate by the laser beam applied thereto, and second plasma light emitted from the electrode pad; and a laser beam irradiation finishing step of stopping application of the laser beam when the second plasma light is detected in the detecting step. A peak power density of the laser beam to be applied is set in a range from 175 GW/cm2 or less to 100 GW/cm2 or more.

Abstract: A laser processing method for applying a laser beam to the reverse side of a substrate with a device formed on a face side thereof and including an electrode pad, to form a pore in the substrate that leads to the electrode pad, includes an irradiation area setting step of detecting the size of the electrode pad and setting an irradiation area for the laser beam such that the pore to be formed is positioned within the electrode pad. After the irradiation area setting step has been performed, the laser beam is applied to the reverse side of the substrate to form a pore in the substrate at a position corresponding to the electrode pad. First plasma light emitted from the substrate and second plasma light emitted from the electrode pad are detected. When the second plasma light is detected, the beam is stopped from being applied to the substrate.