Abstract: Disclosed herein is a method of forming a gettering layer for capturing metallic ions on the back side of a semiconductor wafer formed with devices on the face side thereof. The method includes irradiating the back-side surface of the semiconductor wafer with a pulsed laser beam having a pulse width corresponding to a thermal diffusion length of 10 to 230 nm, to thereby form the gettering layer.

Abstract: A laser processing method of applying a pulsed laser beam having a repetition frequency of 20 kHz or more to a workpiece to thereby process the workpiece. The relation between the wavelength of the pulsed laser beam and the pulse width generating no cracks is determined by experiment on the basis of the absorption edge of the workpiece, thereby setting the processing conditions. The relation between various set values for the wavelength and the limits of the pulse width is plotted to prepare a graph having a vertical axis representing the wavelength and a horizontal axis representing the pulse width. The pulsed laser beam is applied in the region below a curve obtained by connecting the limits of the pulse width at the various set values for the wavelength.

Abstract: A laser beam processing machine comprising a laser beam application means for applying a laser beam to a workpiece held on a chuck table, a processing-feed means, an indexing-feed means, a processing-feed amount detection means for detecting the amount of feed, an indexing-feed amount detection means, and a control means, wherein the condenser constituting the laser beam application means comprises an elliptic spot forming means for forming a focal spot into an elliptic shape and a focal spot turning means for turning the elliptic focal spot on an optical axis at the center thereof; and the control means comprises a storage means for storing the X, Y coordinate values of a processing line formed on the workpiece, obtains the X, Y coordinate values of the current position of a laser beam application position based on detection signals from the processing-feed amount detection means and the indexing-feed amount detection means, and controls the focal spot turning means to ensure that the long axis of the focal

Abstract: A laser processed hole is formed in a workpiece. The workpiece has a first member formed of a first material bonded to a second member formed of a second material. The laser processed hole extends through the first member to the second member. The wavelength of plasma light generated by applying a pulsed laser beam to the first member and the second member is detected. Application of the laser beam is continued at a first power until the plasma light intensity generated from only the first member is decreased to reach a predetermined value. The laser beam is applied at a second power which is lower than the first power so as to not generate cracks in the first member when the plasma light intensity has reached the predetermined value. Application of the plasma laser beam stops when plasma light generated from the second member is detected.

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 processing method for a semiconductor wafer including a groove forming step of applying a pulsed laser beam having an absorption wavelength to the semiconductor wafer along a division line formed on the semiconductor wafer to thereby form a laser processed groove along the division line on the semiconductor wafer, wherein the pulse width of the pulsed laser beam to be applied in the groove forming step is set to 2 ns or less, and the peak energy density per pulse of the pulsed laser beam is set less than or equal to an inflection point where the depth of the laser processed groove steeply increases with an increase in the peak energy density.

Abstract: A laser beam processing machine comprising a laser beam application means for applying a laser beam to a workpiece held on a chuck table and a processing-feed means, wherein the laser beam application means comprises a first pulse laser beam application means and a second pulse laser beam application means; the first pulse laser beam application means comprises an acousto-optic deflection means for deflecting the optical axis of a pulse laser beam oscillated by a first pulse laser beam oscillation means in the processing-feed direction (X direction), and a first condenser lens for converging a pulse laser beam passing through the acousto-optic deflection means; the second pulse laser beam application means comprises a second condenser lens for converging a pulse laser beam oscillated by the second pulse laser beam oscillation means; and an NA value of the first condenser lens is set smaller than the NA value of the second condenser lens.

Abstract: A laser processing apparatus including a laser applying unit. The laser applying unit includes a first laser oscillating unit, a second laser oscillating unit, a first laser branching unit for branching a laser beam oscillated from the first laser oscillating unit into three optical paths, a second laser branching unit for branching a laser beam oscillated from the second laser oscillating unit into three optical paths, three first focusing units for respectively focusing the laser beams through the three optical paths obtained by the first laser branching unit toward a glass substrate, and three second focusing units for respectively focusing the laser beams through the three optical paths obtained by the second laser branching unit. The first focusing units and the second focusing units are alternately arranged in a line in an indexing direction.

Abstract: A hole forming method of forming a laser processed hole in a workpiece configured by bonding a first member formed of a first material and a second member formed of a second material. The hole forming method includes a minimum shot number setting step of setting as a minimum value the number of shots of a pulsed laser beam applied to the workpiece at the time the spectral wavelength of plasma has changed from the spectral wavelength inherent in the first material to the spectral wavelength inherent in the second material, and a maximum shot number setting step of setting as a maximum value the number of shots of the pulsed laser beam at the time the spectral wavelength of the plasma has completely changed.

Abstract: A method of processing an optical device wafer having an optical device layer including an n-type semiconductor layer and a p-type semiconductor layer stacked over a sapphire substrate, a buffer layer therebetween, allowing peeling of the sapphire substrate. The method includes joining a transfer substrate to the optical device layer, breaking the buffer layer by irradiation with a pulsed laser beam from the sapphire substrate side of the wafer with the transfer substrate joined to the optical device layer, and peeling the sapphire substrate from the optical device wafer with the buffer layer broken, transferring the optical device layer onto the transfer substrate. The pulsed laser beam has a wavelength longer than an absorption edge of the sapphire substrate and shorter than an absorption edge of the buffer layer, and a pulse width set so that a thermal diffusion length will be not more than 200 nm.

Abstract: A laser processing apparatus includes a chuck table for holding a workpiece and a laser beam applying unit for applying a laser beam to the workpiece. A laser beam oscillating unit oscillates a laser beam and a focusing unit focuses the laser beam onto the workpiece. A reflecting unit is provided on the optical axis of the focusing unit. A wavelength detecting unit detects the wavelength of the plasma light reflected by the reflecting unit, and a controller determines the material of the workpiece according to a detection signal from the wavelength detecting unit, to control the laser beam applying unit.

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 subject area roughened by the application of the first pulsed laser beam immediately after performing the first laser processing step, thereby forming a recess in the subject area. The first laser processing step and the second laser processing step are repeated to thereby form a continuous groove in the subject area.

Abstract: A laser processing apparatus including a laser beam applying unit. The laser beam applying unit includes a laser beam generating unit, a focusing unit, and an optical system for guiding a laser beam from the laser beam generating unit to the focusing unit.

Abstract: A laser processing method for a nonlinear crystal substrate having a plurality of crossing division lines which includes the step of applying a pulsed laser beam to a work surface of the nonlinear crystal substrate along the division lines to thereby form a plurality of laser processed grooves on the work surface along the division lines. The pulse width of the pulsed laser beam is set to 200 ps or less and the repetition frequency of the pulsed laser beam is set to 50 kHz or less.

Abstract: A device processing method for improving the die strength of a device divided from a semiconductor wafer. The device processing method includes a chamfering step of applying a pulsed laser beam having an absorption wavelength to the device along the periphery of the device to thereby chamfer the periphery of the device, wherein the pulse width of the pulsed laser beam to be applied in the chamfering step is set to 2 ns or less, and the peak energy density is set in the range of 5 to 200 GW/cm2.

Abstract: A laser beam processing machine comprising a chuck table for holding a workpiece, a laser beam application means for applying a laser beam to the workpiece held on the chuck table, a processing feed means for moving the chuck table and the laser beam application means relative to each other in a processing-feed direction and an indexing-feed means for moving the chuck table and the laser beam application means in an indexing-feed direction perpendicular to the processing-feed direction, wherein the laser beam application means comprises a first laser beam application means for applying a first pulse laser beam having an energy density per one pulse of 20 to 60 J/cm2 and a second laser beam application means for applying a second pulse laser beam having an energy density per one pulse of 3 to 20 J/cm2.

Abstract: A laser processing method for a semiconductor wafer including a groove forming step of applying a pulsed laser beam having an absorption wavelength to the semiconductor wafer along a division line formed on the semiconductor wafer to thereby form a laser processed groove along the division lines on the semiconductor wafer, wherein the pulse width of the pulsed laser beam to be applied in the groove forming step is set to 2 ns or less, and the peak energy density is set in the range of 5 to 200 GW/cm2.

Abstract: An optical device layer (ODL) in an optical device wafer is transferred to a transfer substrate. The ODL is formed on the front side of an epitaxy substrate through a buffer layer. The ODL is partitioned by a plurality of crossing streets to define regions where a plurality of optical devices are formed. The transfer substrate is bonded to the front side of the ODL, and the epitaxy substrate is cut along crossing streets into a plurality of blocks. A laser beam is applied to the epitaxy substrate from the back side of the epitaxy substrate to the unit of the optical device wafer and the transfer substrate in the condition where the focal point of the laser beam is set in the buffer layer, thereby decomposing the buffer layer. The epitaxy substrate divided into the plurality of blocks is peeled off from the ODL.

Abstract: An optical device wafer processing method for dividing an optical device wafer into a plurality of individual optical devices. The optical device wafer is composed of a substrate and a semiconductor layer formed on the front side of the substrate. The optical devices are partitioned by a plurality of crossing division lines formed on the semiconductor layer.

Abstract: An optical device wafer processing method for dividing an optical device wafer into a plurality of individual optical devices. The optical device wafer is composed of a substrate and a semiconductor layer formed on the front side of the substrate. The optical devices are partitioned by a plurality of crossing division lines formed on the semiconductor layer.