Abstract: A heat-peelable adhesive sheet which comprises a substrate and, formed on at least one side thereof, a heat-expandable layer containing heat-expandable microspheres and an adhesive layer comprising an adhesive substance and in which the substrate has heat resistance and stretchability can be used to cut an adherend so as to form and secure a sufficient space between the resultant cut pieces and can withstand a heat treatment for expanding the heat-expandable layer. Consequently, the adhesive sheet can heighten the operating efficiency and working efficiency in the step of separating and recovering the cut pieces.

Abstract: The re-peelable pressure-sensitive adhesive sheet of the invention is a re-peelable pressure-sensitive adhesive sheet, which comprises an adhesive agent layer formed over a base film, and which further comprises at least one intermediate layer between the base film and the adhesive agent layer, the intermediate layer having a storage elastic modulus (G?) of 3.0×104 to 1.0×108 Pa at 23° C. and a storage elastic modulus (G?) of 1.0×103 to 8.0×104 Pa at 200° C. Even when this re-peelable pressure-sensitive adhesive sheet and a semiconductor wafer are adhered to each other and they are placed, as they are, in a heating environment, the wafer can be prevented from being warped.

Abstract: A heat-peelable double-faced pressure-sensitive adhesive sheet which comprises a substrate (a), a heat-peelable pressure-sensitive adhesive layer (b) formed on one side of the substrate (a) and containing heat-expandable microspheres, and a pressure-sensitive adhesive layer (c) formed on the other side of the substrate (a), wherein the heat-peelable pressure-sensitive adhesive layer (b) and the substrate (a) are peelable from each other by heating.

Abstract: A method of overheating and releasing a chip cut piece from a thermal release type pressure sensitive adhesive sheet is a method by which a chip cut piece stuck onto a thermal release type pressure sensitive adhesive sheet having a base material, and a thermally expandable microsphere-containing thermally expandable pressure sensitive adhesive layer provided on a surface of the base material is thermally released from the thermal release type pressure sensitive adhesive sheet and which is characterized by including the step of overheating while restraining the overheat and release type pressure sensitive adhesive sheet to thereby release the chip cut piece. A means for restraining the thermal release type pressure sensitive adhesive sheet may be an absorption means using suction or may be a bonding means using an adhesive agent.

Abstract: A heat-peelable pressure-sensitive adhesive sheet comprises: a base material; and a thermo-expandable pressure-sensitive adhesive layer containing thermo-expandable microspheres, the thermo-expandable pressure-sensitive adhesive layer having a surface to be adhered to an adherend, wherein the surface of the thermo-expandable pressure-sensitive adhesive layer before subjecting to heating has a centerline average roughness of greater than 0.4 &mgr;m, and has a convex portion resulting from the thermo-expandable microspheres.

Abstract: An energy-beam-curable thermal-releasable pressure-sensitive adhesive sheet having, on at least one side of a base material, an energy-beam-curable thermo-expandable viscoelastic layer containing thermo-expandable microspheres and a pressure-sensitive adhesive layer stacked in this order. The pressure-sensitive adhesive layer has a thickness of about 0.1 to 10 &mgr;m and can be formed from a pressure-sensitive adhesive. The energy-beam-curable thermo-expandable viscoelastic layer, on the other hand, can be formed from a tacky substance. The energy-beam-curable thermal-releasable pressure-sensitive adhesive sheet according to the invention has adhesion enough to withstand a carrying step of an adherend, causes neither winding up of the adhesive nor chipping upon cutting and facilitates peeling and collection of cut pieces after cutting. In addition, it exhibits low contamination on the adherend after peeling.

Abstract: An energy-beam-curable thermal-releasable pressure-sensitive adhesive sheet has, on at least one side of a base material, an energy-beam-curable viscoelastic layer and a thermo-expandable pressure-sensitive adhesive layer containing thermo-expandable microspheres stacked in this order. The energy-beam-curable viscoelastic layer is, for example, composed of a composition of an organic viscoelastic body and an energy-beam-curable compound or an energy-beam-curable resin. The energy-beam-curable viscoelastic layer has a thickness of about 5 to 300 &mgr;m or may be not greater than the maximum particle size of the thermo-expandable microspheres. The energy-beam-curable thermal-releasable pressure-sensitive adhesive layer according to the invention has adhesion enough to withstand a carrying step of an adherend, causes neither winding up of the adhesive nor chipping upon cutting and facilitates peeling and collection of cut pieces after cutting.

Abstract: A heat-peelable adhesive sheet which comprises a substrate and, formed on at least one side thereof, a heat-expandable layer containing heat-expandable microspheres and an adhesive layer comprising an adhesive substance and in which the substrate has heat resistance and stretchability can be used to cut an adherend so as to form and secure a sufficient space between the resultant cut pieces and can withstand a heat treatment for expanding the heat-expandable layer. Consequently, the adhesive sheet can heighten the operating efficiency and working efficiency in the step of separating and recovering the cut pieces.

Abstract: A heat-peelable pressure-sensitive adhesive sheet which ensures an efficient contact area even in case where the area of an adherend to be adhered is decreased and thus makes it possible to avoid adhesion failures such as chip-scattering or chipping. The heat-peelable pressure-sensitive adhesive sheet comprises a substrate and a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres, formed on at least one side of the substrate, wherein the surface of the heat-expandable pressure-sensitive adhesive layer before heating has a center line average roughness of 0.4 &mgr;m or less.

Abstract: A heat-peelable adhesive sheet which shows small increase in the degree of contamination caused by a heat treatment for lowering an adhesive force is disclosed. The heat-peelable pressure sensitive adhesive sheet comprises a heat-expandable layer containing heat-expandable microspheres and expanding upon heating, and. a non-heat expandable pressure-sensitive adhesive layer formed on at least one side thereof. The heat-peelable pressure-sensitive adhesive sheet can achieve the desired adhesive properties such as an excellent adhesive force before heating and also show a quick lowering of the adhesive force upon heating. Further, it shows small increase in the degree of contamination due to the treatment for lowering the adhesive force. Due to those characteristics, the heat-peelable pressure-sensitive adhesive sheet is practically applicable to, for example, the production of electronic parts made of thinner semiconductor wafers.

Abstract: A radiation-curable heat-peelable pressure-sensitive adhesive sheet is disclosed which has tackiness enabling adherends to withstand transportation and other steps, with which cutting can be conducted without flinging up an adhesive waste or causing chipping, and from which the cut pieces can be easily separated and recovered. The radiation-curable heat-peelable pressure-sensitive adhesive sheet comprises a substrate and, formed on at least one side thereof, a pressure-sensitive adhesive layer containing heat-expandable microspheres and a radiation-curable compound. A work to be cut is placed on the surface of the pressure-sensitive adhesive layer of the radiation-curable heat-peelable pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive layer is irradiated with a radiation to cure the adhesive layer. The work is cut into pieces and the pressure-sensitive adhesive layer is then thermally foamed, before the cut pieces are separated and recovered from the adhesive sheet.

Abstract: A heat-peelable pressure-sensitive adhesive sheet which, even when used for temporarily fixing electronic parts having poor resistance to static electricity, such as magnetic heads, is effective in preventing the yield of such electronic parts from being reduced by electrostatic breakage, while ensuring its functions of adhesiveness before heating and peelability after heating. The heat-peelable pressure-sensitive adhesive sheet comprises a substrate and formed on at least one side thereof a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres, wherein the heat-expandable pressure-sensitive adhesive layer has a surface resistivity of 1012 &OHgr;/□ or lower. In this heat-peelable pressure-sensitive adhesive sheet, the heat-expandable pressure-sensitive adhesive layer before heating may have a center line average surface roughness of 2 &mgr;m or less and a maximum surface roughness of 5 &mgr;m or less.

Abstract: A radiation-curable heat-peelable pressure-sensitive adhesive sheet is disclosed which has tackiness enabling adherends to withstand transportation and other steps, with which cutting can be conducted without flinging up an adhesive waste or causing chipping, and from which the cut pieces can be easily separated and recovered. The radiation-curable heat-peelable pressure-sensitive adhesive sheet comprises a substrate and, formed on at least one side thereof, a pressure-sensitive adhesive layer containing heat-expandable microspheres and a radiation-curable compound. A work to be cut is placed on the surface of the pressure-sensitive adhesive layer of the radiation-curable heat-peelable pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive layer is irradiated with a radiation to cure the adhesive layer. The work is cut into pieces and the pressure-sensitive adhesive layer is then thermally foamed, before the cut pieces are separated and recovered from the adhesive sheet.