Abstract: A pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer and a substrate layer configured to support the pressure-sensitive adhesive agent layer. The pressure-sensitive adhesive layer has a storage modulus of 250 kPa or less at 23° C. The substrate layer has an elastic modulus of 1680 N/cm to 3000 N/cm both inclusive. The pressure-sensitive adhesive sheet shows a deviation amount less than 1.0 mm. The amount is the deviation amount of the pressure-sensitive adhesive sheet per 250 gf/cm2 of the sheet in a holding ability test at 80° C. after one hour from a time when the test is started.

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: An electrostatic chuck table for holding a workpiece includes: a plate-shaped base transmittable with respect to a laser beam having a predetermined wavelength allowing the laser beam to be transmitted through the workpiece, the plate-shaped base having a first surface and a second surface opposite the first surface; an electrostatic attraction electrode assembly transmittable with respect to the laser beam having the predetermined wavelength, the electrostatic attraction electrode assembly being formed on the first surface of the base; and a resin layer transmittable with respect to the laser beam having the predetermined wavelength, the resin layer covering the electrode assembly and providing a holding surface for holding the workpiece thereon. The electrostatic chuck table is used in forming a modified layer within the workpiece held on the holding surface with the laser beam that is applied to the workpiece from the side of the second surface of the base.

Abstract: Provided is a PSA sheet for use in electronic devices suitable for their downsizing and densification. The PSA sheet for electronic devices provided by this invention comprises a substrate and a PSA layer provided to at least one face of the substrate. The PSA sheet has a laser absorbance of 20% or higher in a wavelength range of 1000 nm to 1100 nm; has a thermal shrinkage SMD in its machine direction and a thermal shrinkage STD in its transverse direction (direction perpendicular to the machine direction) of both ?2 % or greater and 2% or less; and has an amount of thermally released gas of 1300 ng/cm2 or less when determined at 80° C. for 3 hours by GC/MS.

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: An electrostatic chuck table includes a plate-shaped base portion capable of transmitting a laser beam to be applied to a workpiece and an electrostatic attraction electrode portion capable of transmitting the laser beam. The laser beam has a transmission wavelength to the workpiece. The base portion has a first surface and a second surface opposite to the first surface. The electrode portion is formed on the first surface of the base portion. A method for using the electrostatic chuck table includes a workpiece holding step of applying a voltage to the electrode portion formed on the first surface to thereby electrostatically hold the workpiece on the second surface, and a modified layer forming step of applying the laser beam through the first surface to a predetermined position inside the workpiece held on the second surface to thereby form a modified layer inside the workpiece.

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.

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: Provided is a PSA sheet having first and second faces. The first face is an adhesive face formed of one surface of a PSA layer. The first face has a maximum static friction force of 4.0 N/cm2 or less and an adhesive strength N2 of 8 N/20mm or greater at 23° C. after subjected to 5 minutes of heating at 80 ° C. after the first face is applied to a stainless steel plate.

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: The present invention provides a pressure-sensitive adhesive (PSA) sheet that achieves both low initial adhesiveness and strong adhesiveness upon use and has excellent transparency of the PSA layer. The PSA sheet provided herein includes a PSA layer having a haze value of 1.0% or less. The PSA sheet is configured so that a pressure-sensitive adhesive strength N1, after the PSA layer is attached to a stainless steel plate and left at 23° C. for 30 minutes, is 1.5 N/20 mm or less, and a pressure-sensitive adhesive strength N2, after the PSA layer is attached to a stainless steel plate and heated at 80° C. for 5 minutes, is 10.0 N/20 mm or more.

Abstract: The present invention provides a pressure-sensitive adhesive (PSA) sheet that achieves, in the form having a support substrate, both low initial adhesiveness and strong adhesiveness during use. The PSA sheet provided in this application includes a support substrate and a PSA layer laminated on at least one side of the support substrate. The PSA layer has a thickness of 3 ?m or more but less than 100 ?m. The support substrate has a thickness of 30 ?m or more. The PSA sheet is configured so that a relationship between an elastic modulus Et? [MPa] of the PSA sheet and a thickness Ts [mm] of the support substrate fulfils the following formula: 0.1 [N·mm]<Et?×(Ts)3. The adhesive strength N2 after the PSA layer is attached to a stainless steel plate (SUS304BA plate) and heated at 80° C. for 5 minutes is 20 times or more of an adhesive strength N1 after the PSA layer is attached to a stainless steel plate (SUS304BA plate) and left at 23° C. for 30 minutes.

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: 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: An electrostatic chuck table includes a plate-shaped base portion capable of transmitting a laser beam to be applied to a workpiece and an electrostatic attraction electrode portion capable of transmitting the laser beam. The laser beam has a transmission wavelength to the workpiece. The base portion has a first surface and a second surface opposite to the first surface. The electrode portion is formed on the first surface of the base portion. A method for using the electrostatic chuck table includes a workpiece holding step of applying a voltage to the electrode portion formed on the first surface to thereby electrostatically hold the workpiece on the second surface, and a modified layer forming step of applying the laser beam through the first surface to a predetermined position inside the workpiece held on the second surface to thereby form a modified layer inside the workpiece.

Abstract: A magnetic disk drive includes a base having an opening, a cover configured to close the opening of the base, and a pressure-sensitive adhesive sheet configured to seal a gap between the base and the cover. The pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer, and a substrate layer configured to support the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer has a storage modulus of 250 kPa or less at 23° C. The substrate layer has an elastic modulus of 1,680 N/cm to 3,000 N/cm. The pressure-sensitive adhesive sheet shows a deviation amount less than 1.0 mm, the amount being the deviation amount of the pressure-sensitive adhesive sheet per 250 gf/cm2 of the sheet in a holding ability test at 80° C. after one hour from a time when the holding ability test is started. Helium gas is accommodated in a cavity defined by the base and the cover.

Abstract: An electrostatic chuck table for holding a workpiece includes: a plate-shaped base transmittable with respect to a laser beam having a predetermined wavelength allowing the laser beam to be transmitted through the workpiece, the plate-shaped base having a first surface and a second surface opposite the first surface; an electrostatic attraction electrode assembly transmittable with respect to the laser beam having the predetermined wavelength, the electrostatic attraction electrode assembly being formed on the first surface of the base; and a resin layer transmittable with respect to the laser beam having the predetermined wavelength, the resin layer covering the electrode assembly and providing a holding surface for holding the workpiece thereon. The electrostatic chuck table is used in forming a modified layer within the workpiece held on the holding surface with the laser beam that is applied to the workpiece from the side of the second surface of the base.

Abstract: A wafer processing method for dividing a wafer into individual device chips along division lines is disclosed. The wafer processing method includes a back grinding step of grinding the back side of the wafer in the condition where a protective tape is attached to the front side of the wafer, thereby reducing the thickness of the wafer to a predetermined thickness, and a reinforcing insulation seal mounting step of mounting a reinforcing insulation seal capable of transmitting infrared light on the back side of the wafer. The wafer processing method further includes a modified layer forming step of applying a laser beam along each division line to thereby form a modified layer inside the wafer along each division line and a wafer dividing step of applying an external force to the wafer to thereby divide the wafer into the individual device chips along each division line.

Abstract: A pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer and a substrate layer configured to support the pressure-sensitive adhesive agent layer. The pressure-sensitive adhesive layer has a storage modulus of 250 kPa or less at 23° C. The substrate layer has an elastic modulus of 1680 N/cm to 3000 N/cm both inclusive. The pressure-sensitive adhesive sheet shows a deviation amount less than 1.0 mm The amount is the deviation amount of the pressure-sensitive adhesive sheet per 250 gf/cm2 of the sheet in a holding ability test at 80° C. after one hour from a time when the test is started.

Abstract: A pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer and a base including a metal layer and a resin layer, and a product of an initial elastic modulus of the base and a total thickness of the base is 3000 N/mm or less, and a separation distance is 2 mm or less, the separation distance is measured with a peel test with a constant load as follows: a test piece of the pressure-sensitive adhesive sheet having a 10 mm width and a 100 mm length is attached to a surface of a stainless steel test plate and then, the test plate is left standing at a temperature of 23° C. for twenty four hours and then, a load of 100 gf is applied to one end of a length dimension of the test piece vertical to the surface of the test plate and a separation distance of the test piece is measured after one hour.