Abstract: A laser optical system and an adjustment method therefor, and a laser machining device and method capable of adjusting laser light so as to satisfy criteria of laser machining are provided. The adjustment method of a laser optical system including a plurality of optical element units which are arranged in series on an optical path of laser light and each of which includes a half-wave plate and a Wollaston prism, the laser optical system configured to branch the laser light incident on the Wollaston prism through the half-wave plate into two beams of branched laser light, includes a step of rotating the half-wave plate around the optical path to adjust branching ratios of the branched laser light and a step of rotating the Wollaston prism around the optical path to adjust branching directions of the branched laser light.

Abstract: Provided are a method and a device for adjusting an optical axis of laser light, capable of accurately grasping change in the state of the laser light and maintaining the quality of laser processing. The method for adjusting an optical axis of laser light includes: a step of detecting a position of laser light by position sensitive detectors arranged at two or more detection positions on an optical path of the laser light that is output from a laser light source toward a workpiece; and a step of adjusting, based on the detected position of the laser light, at least one of a position and an angle of optical elements arranged at two or more positions on the optical path of the laser light, to adjust an optical axis of the laser light.

Abstract: The laser light correction method includes: a step of performing trimming machining on a positioning workpiece in which a laser irradiation surface includes a material that facilitates detection of a laser-irradiation mark, the trimming machining in which a split laser is focused on the laser irradiation surface via a laser optical system while moving the laser optical system in the machining feed direction relative to the positioning workpiece to form a first groove having two rows parallel to each other in a machining feed direction, and performing hollowing machining in which a line laser is focused on the laser irradiation surface via the laser optical system to form a second groove; a step of detecting the first groove and the second groove by a microscope; and a step of correcting focus positions of the split laser and the line laser based on detection results of the first and second grooves.

Abstract: A branching element configured to branch a second laser light into a plurality of beams of branch light along a machining feed direction, and a second condenser lens configured to focus the plurality of beams of branch light branched by a branching element onto a street to be machined are provided, and a time period ? is expressed as ?=L/V, where L is a branch distance, which corresponds to spacing between adjacent leading and trailing spots for each of branch lights focused on the street by the second condenser lens, V is a machining speed, which corresponds to a speed of relative movement, and ? is the time period taken until the trailing spot overlaps a machining position of the leading spot, and ?>?1 is satisfied, where ?1 is a threshold value of the time period when deterioration of the machining quality of the second groove occurs.

Abstract: The laser machining device includes an observation image acquiring unit configured to repeatedly acquire an observation image of a machining spot of laser light emitted from a laser optical system to a street on a wafer while a machined groove is being formed, a luminance detector configured to detect a luminance of a plasma generated at the machining spot by emission of the laser light based on the observation image every time the observation image acquiring unit acquires the observation image, a correspondence information obtaining unit configured to obtain correspondence information indicating a correspondence relationship among the luminance, energy of the laser light and a machined state of the machined groove, and a machined state assessing unit configured to assess the machined state with reference to the correspondence information based on the luminance and known energy of the laser light every time the luminance detector detects the luminance.

Abstract: A laser processing apparatus includes a melt processing unit for processing a melt formed by laser processing, the melt processing unit being disposed downstream of a condenser in a laser beam irradiating direction. The melt processing unit includes a gas injecting section having an opening allowing the passage of a laser beam applied from the condenser, the gas injecting section injecting high-speed gas from the opening to a workpiece, and a melt sucking section having a suction port disposed so as to surround the opening of the gas injecting section, the suction port sucking the melt scattered by the high-speed gas injected from the opening. The gas injecting section is connected to high-pressure gas supply source, and the melt sucking section is connected to melt sucking unit.

Abstract: A laser processing apparatus includes a melt processing unit for processing a melt formed by laser processing, the melt processing unit being disposed downstream of a condenser in a laser beam irradiating direction. The melt processing unit includes a gas injecting section having an opening allowing the passage of a laser beam applied from the condenser, the gas injecting section injecting high-speed gas from the opening to a workpiece, and a melt sucking section having a suction port disposed so as to surround the opening of the gas injecting section, the suction port sucking the melt scattered by the high-speed gas injected from the opening. The gas injecting section is connected to high-pressure gas supply source, and the melt sucking section is connected to melt sucking unit.

Abstract: An optical device including a substrate and a light emitting layer formed on the front surface of the substrate. The back surface of the substrate is formed with a concave portion like a crater. The concave portion is formed by applying a laser beam having an absorption wavelength to an optical device wafer. In the optical device, light emitted from the light emitting layer strikes the inner surface of the concave portion and is next irregularly reflected from the inner surface of the concave portion.

Abstract: A wafer processing method divides a wafer into a plurality of individual devices along a plurality of crossing division lines formed on the front side of the wafer. The method includes a functional layer removing step of applying a CO2 laser beam to the wafer along each division line with the spot of the CO2 laser beam, having a width corresponding to the width of each division line set on the upper surface of each division line, thereby removing a functional layer along each division line to form a groove along each division line where the functional layer has been removed, and a groove shaping and debris removing step of applying a laser beam having a wavelength in the ultraviolet region to the wafer along each groove, thereby removing debris sticking to the bottom surface of each groove and also shaping the side walls of each groove.

Abstract: A wafer processing method divides a wafer into a plurality of individual devices along a plurality of crossing division lines formed on the front side of the wafer. The method includes a functional layer removing step of applying a CO2 laser beam to the wafer along each division line with the spot of the CO2 laser beam, having a width corresponding to the width of each division line set on the upper surface of each division line, thereby removing a functional layer along each division line to form a groove along each division line where the functional layer has been removed, and a groove shaping and debris removing step of applying a laser beam having a wavelength in the ultraviolet region to the wafer along each groove, thereby removing debris sticking to the bottom surface of each groove and also shaping the side walls of each groove.

Abstract: A wafer dividing apparatus for dividing a wafer along a plurality of crossing streets in the condition where the wafer is attached to the upper surface of a dicing tape supported to an annular frame and the strength of the wafer is reduced along the streets. The wafer dividing apparatus includes a frame holding unit for holding the annular frame, a wafer holding table having a holding surface for holding the wafer through the dicing tape supported to the annular frame held by the frame holding unit, a tape expanding unit for relatively moving the frame holding unit and the wafer holding table in a direction perpendicular to the holding surface of the wafer holding table to thereby expand the dicing tape, and a vibration generating unit for applying vibration to the holding surface of the wafer holding table.

Abstract: A wafer dividing apparatus for dividing a wafer along a plurality of crossing streets in the condition where the wafer is attached to the upper surface of a dicing tape supported to an annular frame and the strength of the wafer is reduced along the streets. The wafer dividing apparatus includes a frame holding unit for holding the annular frame, a wafer holding table having a holding surface for holding the wafer through the dicing tape supported to the annular frame held by the frame holding unit, a tape expanding unit for relatively moving the frame holding unit and the wafer holding table in a direction perpendicular to the holding surface of the wafer holding table to thereby expand the dicing tape, and a vibration generating unit for applying vibration to the holding surface of the wafer holding table.

Abstract: A laser processing method for processing a wafer including a substrate layer and a device layer composed of a plurality of devices formed on the front side of the substrate layer, wherein a laser beam is applied to the wafer from the back side in a defocused condition where the focal position of the laser beam is spaced apart from the surface position of the substrate layer on the back side by a predetermined distance.