Abstract: A laser processing method of applying a laser beam to a workpiece having a plurality of members, thereby forming a laser processed groove on the workpiece. The laser processing method includes the steps of setting a plurality of processing conditions respectively corresponding to a plurality of different materials forming the plurality of members constituting the workpiece, detecting the wavelengths of plasma lights generated by applying the laser beam to the plurality of members constituting the workpiece, selecting any suitable one of the processing conditions corresponding to any one of the members corresponding to the wavelength of plasma lights detected above, and applying the laser beam under the processing condition selected above.

Abstract: A laser processing apparatus detects the wavelength of plasma light generated by applying a pulsed laser beam to a workpiece. A plasma detecting unit includes a first bandpass filter for passing only the wavelength of plasma light separated into a first optical path by a beam splitter, a first photodetector for detecting the light passed through the first bandpass filter, a second bandpass filter for passing only the wavelength of plasma light separated into a second optical path by the beam splitter, and a second photodetector for detecting the light passed through the second bandpass filter. In performing laser processing, the pulsed laser beam is stopped when the light intensity detected by the first photodetector is decreased and the light intensity detected by the second photodetector is increased to a peak value and then decreased to a given value slightly less than the peak value.

Abstract: A cutting method for cutting a device wafer along a plurality of crossing division lines by using a cutting blade, the division lines being formed on the front side of the device wafer to partition a plurality of regions where a plurality of devices are respectively formed. The cutting method includes a hydrophilic property providing step of applying a plasma to the front side of the device wafer to thereby make hydrophilic the front side of the device wafer, and a cutting step of cutting the device wafer along the division lines by using the cutting blade as supplying a cutting fluid to the device wafer after performing the hydrophilic property providing step.

Abstract: A laser processing apparatus includes a plasma detecting unit for detecting a wavelength of plasma light generated by applying a pulsed laser beam from a laser beam applying unit to a workpiece. The plasma detecting unit includes a bandpass filter for passing only the wavelength of plasma light generated from a first material and a photodetector for detecting the light passed through the bandpass filter. A light intensity signal is output to a controller. The controller controls the laser beam applying unit so that the amplitude of a light intensity is detected according to the light intensity signal output from the photodetector. The pulsed laser beam is stopped after the amplitude of the light intensity is decreased to a predetermined value and a predetermined number of shots of the pulsed laser beam has been applied.

Abstract: A wafer processing method of dividing a wafer along streets. The wafer processing method includes a protective tape attaching step of attaching a protective tape to the front side of the wafer, a modified layer forming step of holding the wafer through the protective tape on a chuck table of a laser processing apparatus under suction and next applying a laser beam having a transmission wavelength to the wafer from the back side of the wafer along the streets, thereby forming a modified layer inside the wafer along each street, and a wafer dividing step of canceling suction holding of the wafer by the chuck table and next applying an air pressure to the wafer now placed on the holding surface in the condition where horizontal movement of the wafer is limited, thereby dividing the wafer along each street where the modified layer is formed, thus obtaining individual devices.

Abstract: A processing apparatus including a holding unit having a holding surface for holding a platelike workpiece and a processing unit for processing the workpiece held by the holding unit. The processing unit includes a processing wheel opposed to the holding surface of the holding unit, a wheel mount having a supporting surface for detachably supporting the processing wheel, a rotating shaft connected to another surface of the wheel mount opposite to the supporting surface, a housing for rotatably supporting the rotating shaft, a mount cover provided on the housing so as to cover the wheel mount with a predetermined gap defined between the mount cover and the wheel mount, the mount cover having a cleaning water inlet communicating with the predetermined gap, and a cleaning water source connected to the cleaning water inlet.

Abstract: A tool cutting method which includes a correlation table preparing step of preparing a correlation table indicating the correlation between the brightness of light emitted from LED chips and the thickness of a sealing member, a brightness measuring step of measuring the brightness of light emitted from the LED chips by applying a voltage to the LED chips, a calculating step of calculating the thickness of the sealing member corresponding to the desired thickness from the brightness measured in the brightness measuring step and the correlation table, and a cutting step of cutting the sealing member by using a tool cutting unit after performing the calculating step to reduce the thickness of the sealing member to a finished thickness providing the desired brightness of light emitted from the LED chips.

Abstract: The back side of a wafer having a plurality of devices formed on the front side thereof is ground to thereby reduce the thickness of the wafer. A resin layer is formed on the front side of the wafer and is cured. The resin layer is planarized while the back side of the wafer is held on a chuck table and the resin layer formed on the front side of the wafer is exposed. The resin layer is bonded to a hard plate through a bonding member, and the back side of the wafer is ground by using a grinding unit of a grinding apparatus to thereby reduce the thickness of the wafer to a predetermined thickness while the hard plate bonded to the wafer is held on a chuck table of the grinding apparatus.

Abstract: A laser processing apparatus includes a beam diameter adjusting unit provided between a laser oscillator and a focusing unit, an imaging unit for detecting the beam diameter of the laser beam directed to a detection path, an optical path length changing unit for moving the imaging unit along the detection path to thereby change an optical path length, and a controller for controlling the imaging unit, the beam diameter adjusting unit, and the optical path length changing unit. The controller operates to move the imaging unit to two positions where different optical path lengths are provided, detect the beam diameters of the laser beam at the two positions, and controls the beam diameter adjusting unit according to the two beam diameters detected above so that the two beam diameters have a predetermined relation.

Abstract: An optical device wafer processing method for processing an optical device wafer having an epitaxy substrate and an optical device layer formed on the front side of the epitaxy substrate through a buffer layer. The buffer layer of the optical device wafer is to be broken in the condition where the optical device layer of the optical device wafer is bonded through a bonding metal layer to a transfer substrate. The optical device wafer processing method includes a buffer layer breaking step of applying a pulsed laser beam having a wavelength having transmissivity to the epitaxy substrate and having absorptivity to the buffer layer from the back side of the epitaxy substrate to the buffer layer, thereby breaking the buffer layer. The buffer layer breaking step includes a first laser beam applying step of completely breaking the buffer layer corresponding to an optical device area and a second laser beam applying step of incompletely breaking the buffer layer corresponding to a peripheral marginal area.

Abstract: An optical device wafer is divided into individual optical devices along streets. A modified layer is formed by applying a laser beam to a sapphire substrate constituting the optical device wafer along the streets from the back side of the sapphire substrate such that the focal point of the laser beam is set inside the sapphire substrate, thereby forming a modified layer inside the sapphire substrate along each street. A reflective film is formed on the back side of the sapphire substrate and the reflective film is cut by applying a laser beam along the streets from the back side of the sapphire substrate. The wafer is divided by applying an external force to the optical device wafer to thereby break the optical device wafer along each street where the modified layer is formed, so that the optical device wafer is divided into the individual optical devices.

Abstract: A semiconductor wafer processing method forms a plurality of wafer dividing grooves respectively along a plurality of crossing streets formed on the front side of a semiconductor substrate of a semiconductor wafer to thereby partition a plurality of regions where a plurality of devices are respectively formed. The semiconductor wafer has a passivation film formed on the front side of the semiconductor substrate so as to cover the devices and the streets. A first laser beam is applied to the passivation film along each street to thereby form a film dividing groove in the passivation film along each street. A second laser beam is applied to the semiconductor substrate along the film dividing groove formed in the passivation film, thereby forming the wafer dividing groove in the semiconductor substrate along each street.

Abstract: A wafer processing method for reducing the thickness of a wafer to a predetermined thickness, the wafer having a chamfered portion along the outer circumference thereof. The wafer processing method includes a stacked wafer forming step of attaching a support substrate to the front side of the wafer to thereby form a stacked wafer, and a chamfered portion removing step of positioning a cutting blade having a rotation axis parallel to the stacking direction of the stacked wafer formed by the stacked wafer forming step so that the outer circumference of the cutting blade faces the chamfered portion of the wafer, and then making the cutting blade cut into the wafer from the outer circumference toward the center thereof to thereby partially remove the chamfered portion in the range corresponding to the predetermined thickness from the front side of the wafer.

Abstract: A device for indicating the level of a liquid contained in a tank. The liquid level indication device includes: a liquid level measuring unit for measuring the level of the liquid contained in the tank; an indicating unit disposed outside of the tank to indicate the level of the liquid measured by the liquid level measuring unit; and a controller for outputting to the indicating unit a control signal based on a measurement signal obtained on measurement by the liquid level measuring unit. The indicating unit is provided with a plurality of light-emitting elements which are located respectively at positions corresponding to a plurality of positions ranging from an uppermost position to a lowermost position of the level of the liquid contained in the tank. The controller causes the light-emitting elements corresponding to the liquid level measured by the liquid level measuring unit to emit light.

Abstract: A laser processing apparatus removes a sapphire substrate from an optical device wafer configured by forming an optical device layer on the front side of the sapphire substrate through a buffer layer. A chuck table holds the optical device wafer. A pulsed laser beam is applied to the optical device wafer to break the buffer layer, and the light intensity of plasma light produced in the buffer layer by the application of the pulsed laser beam is detected and displayed. The light intensity of a predetermined wavelength region of the plasma light generated from a substance forming the buffer layer is detected.

Abstract: An ablation method of applying a laser beam to a workpiece to perform ablation. The ablation method includes a protective film forming step of applying a liquid resin containing a powder having absorptivity to the wavelength of the laser beam to at least a subject area of the workpiece to be ablated, thereby forming a protective film containing the powder on at least the subject area of the workpiece, and a laser processing step of applying the laser beam to the subject area coated with the protective film, thereby performing ablation through the protective film to the subject area of the workpiece after performing the protective film forming step.

Abstract: An ablation method of applying a laser beam to a substrate on which a passivation film of nitride is formed, thereby performing ablation. The ablation method includes a protective film forming step of applying a liquid resin containing a fine powder of oxide having absorptivity to the wavelength of the laser beam to at least a subject area of the substrate to be ablated, thereby forming a protective film containing the fine powder on at least the subject area of the substrate, and a laser processing step of applying the laser beam to the subject area coated with the protective film, thereby performing ablation through the protective film to the subject area of the substrate after performing the protective film forming step.

Abstract: An ablation method of applying a laser beam to a die attach film to perform ablation. The ablation method includes a protective film forming step of applying a liquid resin containing a fine powder of oxide having absorptivity to the wavelength of the laser beam to at least a subject area of the die attach film to be ablated, thereby forming a protective film containing the fine powder on at least the subject area of the die attach film, and a laser processing step of applying the laser beam to the subject area coated with the protective film, thereby performing ablation through the protective film to the subject area of the die attach film after performing the protective film forming step.