Abstract: A laser beam applying unit of a laser processing apparatus for processing a wafer includes a laser oscillator for emitting a pulsed laser beam having a wavelength transmittable through the wafer, a beam condenser for converging the pulsed laser beam emitted from the laser oscillator onto the wafer held on a chuck table, a beam splitter assembly disposed between the laser oscillator and the beam condenser, for splitting the pulsed laser beam emitted from the laser oscillator to form at least two converged spots on the wafer that are spaced from each other in X-axis directions, and a mask assembly disposed between the laser oscillator and the beam condenser, for reducing the width of the converged spots on the wafer in Y-axis directions to keep the converged spots on the wafer within the width of the projected dicing lines on the wafer.

Abstract: A resin sheet with a pressure-sensitive adhesive layer including the resin sheet. The resin sheet including a main surface A and a main surface B opposite to each other across a thickness “d”, where the resin sheet has a 50% compression load of 20 N/cm2 or less at 23±5° C. in a direction of the thickness “d”, which is measured in conformity with a method of measuring a compression hardness described in JIS K 6767:1999; where the resin sheet has a Poisson's ratio at 23° C. of 0.10 or less; and the resin sheet has a thickness recovery ratio of 40% or more when compressed by 20% in the direction of the thickness “d” at 23° C.

Abstract: A resin sheet with a pressure-sensitive adhesive layer including the resin sheet. The resin sheet including a main surface A and a main surface B opposite to each other across a thickness “d”, where the resin sheet has a 50% compression load of 20 N/cm2 or less at 23±5° C. in a direction of the thickness “d”, which is measured in conformity with a method of measuring a compression hardness described in JIS K 6767:1999; where the resin sheet has a Poisson's ratio at 23° C. of 0.10 or less; and the resin sheet has a thickness recovery ratio of 40% or more when compressed by 20% in the direction of the thickness “d” at 23° C.

Abstract: A wafer dividing method includes forming modified layers which will be starting points of division, integrally attaching an annular frame and the wafer together through a dicing tape, directing the wafer downward and expanding the dicing tape to divide, into individual device chips, the wafer along the modified layers formed along the streets, counting particles scattered at the time of division of the wafer by a particle counter disposed in a dust collection path set directly below the wafer, and determining, on the basis of the number of the particles, whether or not the modified layers have been properly formed, at the time of carrying out the dividing step.

Abstract: A laser processing apparatus includes a condensing lens configured to form a condensing point of an applied laser beam and form a focus of a camera; a focus adjusting unit configured to adjust a height of the focus of the camera by moving a base to which the camera and the condensing lens are fixed in a height direction perpendicular to a holding surface of a chuck table; a condensing point adjusting unit disposed between a laser oscillator and the condensing lens, and configured to shift a height of the condensing point of the laser beam without changing a height of the condensing lens; and a control unit including a registering section configured to register the heights of the condensing point and the focus, the control unit being configured to control the focus adjusting unit and the condensing point adjusting unit on the basis of information of the registering section.

Abstract: A wafer processing method includes an adhesive film bonding step of bonding an adhesive film on a side of a back surface of the wafer, an adhesive film cutting-off step of cutting off at least the adhesive film that is bonded on the side of the back surface of the wafer along streets from the side of the back surface of the wafer, a modified layer forming step of irradiating a laser beam of a wavelength that has transmissivity through the wafer with the laser beam focused inside the wafer, so that modified layers are formed along the streets, respectively, and a dividing step of, after performing the adhesive film cutting-off step and the modified layer forming step, applying an external force to the wafer so that the wafer is divided from the modified layers as starting points.

Abstract: A wafer processing method for processing a wafer with devices formed in regions on a side of a front surface of the wafer, the regions being defined by first scheduled division lines and second scheduled division lines includes a first modified layer forming step and a second modified layer forming step. In the first modified layer forming step, a laser beam is irradiated with its focal point set at a height leveled with a height of a first region located inside the wafer on the side of the front surface of the wafer, whereby first modified layers are formed. In the second modified layer forming step, the laser beam is irradiated with its focal point set at a height leveled with a height of a second region located inside the wafer on a side of a back surface of the wafer, whereby second modified layers are formed.

Abstract: The present invention provides an acrylic PSA composition. The acrylic PSA composition comprises an acrylic polymer as its base polymer and at least one species selected among tackifier resins and (meth)acrylic oligomers. The acrylic polymer has a weight average molecular weight higher than 70×104. The acrylic polymer has a dispersity (Mw/Mn) below 15.

Abstract: A thermally-conductive pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer containing thermally-conductive particles. One side of the sheet is an adhesive face, and the other side is a non-adhesive face. The thermally-conductive pressure-sensitive adhesive sheet may include a non-adhesive layer on or over only one side of the pressure-sensitive adhesive layer. In this case, the ratio of the thickness of the non-adhesive layer to the thickness of the pressure-sensitive adhesive layer is preferably 0.04 to 0.6. The thermally-conductive pressure sensitive adhesive sheet preferably has a thermal resistance of 6 K·cm2/W or less. The thermally-conductive pressure sensitive adhesive sheet preferably has a total thickness of 50 to 500 ?m.

Abstract: A device chip manufacturing method includes adhering a protective member to a side of one surface of a front surface and a back surface of a workpiece including a device wafer, positioning the one surface on a lower side and holding the workpiece under suction by a holding surface, measuring the height of a lower surface and the height of an upper surface of the workpiece, applying a laser beam to the workpiece while adjusting the height of a focal point of the laser beam, to thereby form two or more modified layers at different heights inside the workpiece, and dividing the workpiece into device chips. The applying the laser beam includes forming a first modified layer on the lower surface side according to the height of the lower surface, and forming a second modified layer on the upper surface side according to the height of the upper surface.

Abstract: Provided is a PSA sheet having excellent moisture resistance with reduced gas emission. The sheet body provided by this invention is a laminate sheet body having a PSA layer on at least one face. The sheet body has a moisture permeability of less than 90 ?g/cm2 per 24 hour measurement period in in-plane direction of bonding interface of PSA layer, with the sheet body having an internal volume (bulk) forming a permeation channel that has a prescribed length of 2.5 mm, the moisture permeability determined based on a modified MOCON method, at a permeation cell temperature of 40° C., with humidistat gas at a temperature of 40° C. and 90% relative humidity supplied to a wet chamber. It also has an amount of thermally released gas of 10 ?g/cm2 or less, determined at 130° C., over 30 minutes, by gas chromatography/mass spectrometry.

Abstract: Provided is a PSA composition capable of achieving excellent moisture resistance. The PSA composition provided by the present invention comprises a polymer A and a polymer B different from the polymer A. In each of the polymer A and the polymer B, isobutylene is polymerized at a ratio of 50% by weight or higher.

Abstract: Disclosed herein is an evaluation jig that is a jig to be used for evaluation of a height position detection unit that detects the height position of a holding surface of a chuck table of a laser processing apparatus. The evaluation jig includes a to-be-irradiated surface which is to be irradiated with a detection laser beam, an actuator that moves the to-be-irradiated surface in a Z-axis direction, a base section that supports the actuator and is mounted on the holding surface of the chuck table, and a control unit that controls movement of the actuator.

Abstract: Provided is a thermally conductive PSA sheet that comprises a PSA layer comprising a thermally conductive filler. The PSA sheet has a thermal resistance less than 6.0 cm2·K/W, and also has an adhesive strength N1 at 30 minutes of standing at 23° C. after applied to a stainless steel plate and an adhesive strength N2 at 23° C. after subjected to 5 minutes of heating at 80° C. after applied to a stainless steel plate, satisfying N2/N1?2.

Abstract: A wafer processing method for processing a wafer with devices formed in regions on a side of a front surface of the wafer, the regions being defined by first scheduled division lines and second scheduled division lines includes a first modified layer forming step and a second modified layer forming step. in the first modified layer forming step, a laser beam is irradiated with its focal point set at a height leveled with a height of a first region located inside the wafer on the side of the front surface of the wafer, whereby first modified layers are formed. In the second modified layer forming step, the laser beam is irradiated with its focal point set at a height leveled with a height of a second region located inside the wafer on a side of a back surface of the wafer, whereby second modified layers are formed.

Abstract: A resin sheet with a pressure-sensitive adhesive layer including the resin sheet. The resin sheet including a main surface A and a main surface B opposite to each other across a thickness “d”, where the resin sheet has a 50% compression load of 20 N/cm2 or less at 23±5° C. in a direction of the thickness “d”, which is measured in conformity with a method of measuring a compression hardness described in JIS K 6767:1999; where the resin sheet has a Poisson's ratio at 23° C. of 0.10 or less; and the resin sheet has a thickness recovery ratio of 40% or more when compressed by 20% in the direction of the thickness “d” at 23° C.

Abstract: The invention relates to a method of processing a substrate. The substrate has on a first surface a device area with a plurality of devices partitioned by a plurality of division lines. A pulsed laser beam is applied to the substrate at least in a plurality of positions along each of the division lines, with a focal point located at a distance from the first surface in the direction from the first surface towards a second, opposite surface, so as to form a plurality of modified regions in the substrate along each of the division lines. The second surface of the substrate is then ground to adjust the substrate thickness. After forming modified regions and/or hole regions in the substrate, a plasma can be applied to the substrate so as to form a plurality of grooves extending along the division lines.

Abstract: Provided is a PSA sheet that has a high level of moisture resistance while maintaining good holding power with reduced gas emission. The PSA sheet provided by this invention comprises a moisture-impermeable layer and a PSA layer provided to one face of the moisture-impermeable layer. The PSA layer comprises a polymer A having a weight average molecular weight of 5×104 or higher as a base polymer and a polymer B having a number average molecular weight of 1000 or higher and a weight average molecular weight lower than 5×104.

Abstract: Provided is an electronic device capable of bringing about excellent airtightness. The electronic device provided by this invention comprises a housing that forms an internal space to house components, and a cover seal. The housing has an opening and/or gap through which gases can move between the internal space and outside of the housing. The cover seal is bonded to the housing, covering the opening and/or gap. The cover seal is formed of at least one PSA sheet having a gas barrier layer and a PSA layer provided at least on one face of the gas barrier layer. The bonding interface between the housing and the cover seal has, along its surface, a first bonding area, a non-bonding area and a second bonding area in this order from the opening and/or gap towards the outside.

Abstract: Provided is a PSA sheet that achieves both bonding reliability at a high temperature and reduction of outgassing. The PSA sheet provided by this invention comprises a substrate layer and a PSA layer provided to one face of the substrate layer. The PSA sheet exhibits a 180° peel strength of 1 N/20 mm or greater to stainless steel at 60° C. It has an amount of thermally released gas of 10 ?g/cm2 or less, determined at 130° C. for 30 minutes by GC-MS.