Abstract: A laser oscillation mechanism includes a pulse laser oscillator which oscillates a pulse laser beam, and an optical path changing unit which changes an angle of an optical path of the pulse laser beam oscillated by the pulse laser oscillator. The optical path changing unit is configured from an acousto-optic deflection unit including an acousto-optic device for changing the optical path of the pulse laser beam oscillated by the pulse laser oscillator within an effective region, and a volume Bragg grating which excludes, from among pulse laser beams obtained by changing the angle of the optical path of the pulse laser beam by passing through the acousto-optic device, a pulse laser beam desired to be eliminated by refraction from within the effective region.

Abstract: A laser oscillation mechanism includes a pulse laser oscillator configured to oscillate a pulse laser beam, and a branching unit which branches the pulse laser beam oscillated by the pulse laser oscillator. The branching unit includes a diffraction optical element and a volume Bragg grating. The diffraction optical element branches the pulse laser beam oscillated by the pulse laser oscillator into a plurality of laser beams in an effective region. The volume Bragg grating refracts, from among the pulse laser beams branched by the diffraction optical element, a particular pulse laser beam to be excluded from the effective region to exclude the particular pulse laser beam.

Abstract: Disclosed herein is a laser processing apparatus including a beam swinging unit provided between a pulsed laser oscillator and a focusing unit for swinging the optical path of a pulsed laser beam oscillated from the pulsed laser oscillator and then introducing the pulsed laser beam to the focusing unit. The beam swinging unit includes a polygon scanner provided on the upstream side of the focusing unit for scanning the pulsed laser beam oscillated from the pulsed laser oscillator and introducing the pulsed laser beam scanned to the focusing unit and an acoustooptic deflecting unit provided on the upstream side of the polygon scanner and on the downstream side of the pulsed laser oscillator for deflecting the optical path of the pulsed laser beam oscillated from the pulsed laser oscillator and introducing the pulsed laser beam deflected to the polygon scanner.

Abstract: A laser beam applying apparatus includes a laser beam oscillating unit, a focusing lens, and a diffractive optic element provided between the laser beam oscillating unit and the focusing lens for defining the spot shape of the laser beam oscillated by the laser beam oscillating unit. A zeroth-order light removing unit removes zeroth-order light emerging from the diffractive optic element and leaves first-order light whose spot shape has been defined by the diffractive optic element and the focusing lens. A first prism has an incident surface and an emergent surface inclined with respect to the incident surface. A second prism has a zeroth-order light reflecting surface for reflecting the zeroth-order light and a first-order light emerging surface from which the first-order light emerges. A damper absorbs the zeroth-order light reflected on the zeroth-order light reflecting surface of the second prism.

Abstract: A laser processing apparatus has an optical transmitting unit for guiding a laser beam to a focusing unit. The optical transmitting unit includes a focusing lens for focusing the laser beam, an optical fiber unit for inputting the focused laser beam and guiding it to the focusing unit. The optical fiber unit includes an LMA fiber for inputting the focused laser beam. The LMA fiber has a large-diameter core covered with a cladding, a transmitting fiber provided by an SM fiber or a PM fiber. The transmitting fiber has a small-diameter core covered with a cladding, the small-diameter core having a diameter corresponding to the wavelength of the laser beam oscillated by the laser oscillator. A connector connects the LMA fiber and the transmitting fiber so that these fibers are axially aligned with each other.

Abstract: A height detecting apparatus for detecting the height of a workpiece held on a chuck table. The height detecting apparatus includes a single-mode fiber for transmitting return light reflected from the workpiece and next branched by a fiber coupler, a photodetector for detecting the return light emerging from the single-mode fiber and outputting a signal corresponding to the intensity of the return light detected above, and a controller having a memory for storing a table setting the relation between wavelength and height. The controller determines the wavelength corresponding to the highest light intensity from the wavelengths detected by the photodetector in synchronism with the predetermined cycles of sweeping of light having a single wavelength by a Fabry-Perot tunable filter, and then checks this determined wavelength against the wavelength and height set in the table, thereby determining the height of the workpiece held on the chuck table.

Abstract: A laser machining apparatus has a laser beam irradiation unit that includes: a pulsed laser oscillator that oscillates a pulsed laser beam at a given repetition frequency; first and second condensers that collect the pulsed laser beam oscillated by the pulsed laser oscillator; and a beam splitting unit arranged between the pulsed laser oscillator and the first and second condensers to split the pulsed laser beam oscillated by the pulsed laser oscillator and direct the resultant beams alternately toward the first and second condensers. The beam splitting unit includes a photoelastic modulator that has a piezo element and a synthetic quartz formed in one piece and modulates the laser beam so that a polarization plane of the laser beam is alternately at 0 and 90 degrees by applying, to the piezo element, a high frequency voltage at a frequency that matches the natural frequency of the synthetic quartz.

Abstract: Disclosed herein is a laser beam spot shape detection method for detecting a spot shape of a laser beam oscillated by laser beam oscillator and collected by a condenser in a laser machining apparatus, the laser beam spot shape detection method including: a concave mirror holding step of holding a concave mirror having a spherical face forming a reflecting face with a chuck table; a focal point positioning step of positioning the focal point of the condenser in a proximity including the center of the spherical face forming the reflecting face of the concave mirror held by the chuck table; a laser beam irradiation step of irradiating a laser beam onto the held concave mirror, and an imaging step of capturing images of reflected light with a camera.

Abstract: A laser processing method of applying a pulsed laser beam to a workpiece formed from a transparent member, thereby performing laser processing to the workpiece. The laser processing method includes a first laser processing step of applying a first pulsed laser beam to a subject area of the workpiece to roughen the subject area and a second laser processing step of applying a second pulsed laser beam to the roughened subject area immediately after performing the first laser processing step, thereby forming a recess in the subject area. The first and second laser processing steps are repeated to thereby form a continuous groove in the subject area.

Abstract: A laser processing apparatus including a laser beam branching mechanism provided between a laser oscillator and a focusing unit. The laser beam branching mechanism includes a spread angle adjusting unit for adjusting the spread angle of a laser beam and a branching unit for branching the laser beam into a plurality of laser beams. The branching unit includes a half-wave plate, a first polarization beam splitter for separating the laser beam into P polarized light and S polarized light, a first mirror for reflecting the P polarized light, a second mirror for reflecting the S polarized light, and a second polarization beam splitter for leading the P polarized light reflected by the first mirror and the S polarized light reflected by the second mirror to different optical paths extending in the same direction.

Abstract: A laser processing apparatus includes a laser beam branching mechanism provided between a laser oscillator and a focusing unit. The branching mechanism includes a branching unit for branching a laser beam into a plurality of laser beams. The branching unit includes a half-wave plate for 45° rotating the polarization plane of the laser beam. A first polarization beam splitter separates the laser beam passed through the half-wave plate into P polarized light and S polarized light. A first mirror reflects the P polarized light and a second mirror reflects the S polarized light. A second polarization beam splitter leads the reflected P polarized light and the reflected S polarized light to different optical paths extending in the same direction, and an angle adjusting mechanism adjusts the angle of reflection of at least one of the P polarized light and the S polarized light.

Abstract: A height detecting apparatus for detecting the height of a workpiece held on a chuck table. The height detecting apparatus includes a single-mode fiber for transmitting return light reflected from the workpiece and next branched by a fiber coupler, a photodetector for detecting the return light emerging from the single-mode fiber and outputting a signal corresponding to the intensity of the return light detected above, and a controller having a memory for storing a table setting the relation between wavelength and height. The controller determines the wavelength corresponding to the highest light intensity from the wavelengths detected by the photodetector in synchronism with the predetermined cycles of sweeping of light having a single wavelength by a Fabry-Perot tunable filter, and then checks this determined wavelength against the wavelength and height set in the table, thereby determining the height of the workpiece held on the chuck table.

Abstract: A laser processing apparatus including a workpiece holding unit for holding a workpiece and a laser beam applying unit for applying a laser beam to the workpiece held by the workpiece holding unit. The laser beam applying unit includes a laser oscillator for oscillating a laser beam, a focusing unit for focusing the laser beam oscillated by the laser oscillator onto the workpiece held by the workpiece holding unit, and an optical system provided between the laser oscillator and the focusing unit for transmitting the laser beam oscillated by the laser oscillator. The laser beam applying unit further includes a wavelength converting mechanism provided between the optical system and the focusing unit for converting the wavelength of the laser beam oscillated by the laser oscillator into a short wavelength.

Abstract: A laser machining apparatus includes a chuck table for holding a workpiece, and an irradiation unit which irradiates a laser beam upon the workpiece held on the chuck table. The laser beam irradiation unit includes a condenser which condenses the laser beam and irradiates the condensed laser beam upon the workpiece held on the chuck table. The condenser includes first and second condenser lenses arrayed in series in an advancing direction of the laser beam, a first moving unit having a first driving source for moving the first condenser lens in a first direction perpendicular to an optical axis of the first condenser lens, and a second moving unit having a second driving source for moving the second condenser lens in a second direction perpendicular to the first direction.

Abstract: An unevenness detecting device includes: a pulsed illuminating light source emitting light having a predetermined wavelength range; a first condensing lens condensing return light reflected by a workpiece held on a chuck table and passed through a chromatic aberration lens and a half-silvered mirror; a mask disposed at the position of a focal point of the first condensing lens, the mask passing only the condensed return light; a diffraction grating performing light separation so as to correspond to the wavelengths of the return light; a second condensing lens condensing the return light resulting from the light separation by the diffraction grating; and an imaging element disposed at the position of a focal point of the second condensing lens.

Abstract: A laser processing apparatus including a pulsed laser oscillator for oscillating a pulsed laser beam, a focusing objective lens for focusing the pulsed laser beam, and a varifocal lens provided between the pulsed laser oscillator and the focusing objective lens. The varifocal lens has a piezoelectric device to change its focal length according to the period of radio-frequency waves produced by the piezoelectric device. A repetition frequency adjusting unit is connected to the pulsed laser oscillator, and a radio-frequency current frequency adjusting unit is connected to the piezoelectric device. The laser processing apparatus further includes a controller for controlling the repetition frequency adjusting unit and the radio-frequency current frequency adjusting unit so as to produce a phase difference between the repetition frequency of the pulsed laser beam and the frequency of the radio-frequency current to be applied to the piezoelectric device of the varifocal lens.

Abstract: A wafer is divided into a plurality of individual devices along a plurality of crossing division lines formed on the front side of the wafer. The wafer has a substrate, a functional layer formed on the front side of the substrate, and an SiO2 film formed on the front side of the functional layer. The individual devices are formed from the functional layer and partitioned by the division lines. The functional layer is removed by applying a laser beam to the wafer along each division line to thereby remove the functional layer along each division line. The laser beam has an absorption wavelength to the SiO2 film with high absorptivity due to the stretching vibration of an O—H bond or a C—H bond remaining in the SiO2 film. The wafer is then divided into the individual devices.

Abstract: A laser beam applying mechanism has a power adjusting unit provided between a laser beam oscillator and a focusing lens. The power adjusting unit includes a half-wave plate, a prism having a first polarization beam splitter film and a second polarization beam splitter film. The optical path is adjusted by a piezoelectric actuator opposed to the first polarization beam splitter film, and a polarized light components synthesizer opposed to the second polarization beam splitter film generates a phase difference (?) between an S polarized light component and a P polarized light component. The phase difference (?) between the S polarized light component and the P polarized light component of the laser beam obtained by the polarized light components synthesizer is in the range of 0° to 180°.

Abstract: A wafer is divided into a plurality of individual devices along a plurality of crossing division lines formed on the front side of the wafer. The wafer has a substrate, a functional layer formed on the front side of the substrate, and an SiO2 film formed on the front side of the functional layer. The individual devices are formed from the functional layer and partitioned by the division lines. The functional layer is removed by applying a laser beam to the wafer along each division line to thereby remove the functional layer along each division line. The laser beam has an absorption wavelength to the SiO2 film with high absorptivity due to the stretching vibration of an O—H bond or a C—H bond remaining in the SiO2 film. The wafer is then divided into the individual devices.

Abstract: A pulsed laser beam is applied to a workpiece held on a chuck table by a laser beam applying unit. The laser beam applying unit includes a pulsed laser beam oscillator, a focusing lens, and a piezoelectric motor for displacing the focusing unit in a direction inclined at a predetermined angle (?) with respect to the Z direction. A controller controls the frequency and voltage of an RF current to be applied to the piezoelectric motor in relation to the repetition frequency of the pulsed laser beam to move the focusing unit in the X direction by ?x and in the Z direction by ?z in feeding the chuck table in the X direction, thereby displacing the focal point of the pulsed laser beam to be focused by the focusing lens in the thickness direction of the workpiece held on the chuck table.