Abstract: Disclosed is an ultraviolet-curable pressure sensitive adhesive composition comprising an ultraviolet-curable pressure sensitive adhesive component and a phosphorus type photopolymerization initiator. Also disclosed is an ultraviolet-curable pressure sensitive adhesive sheet obtained by coating a substrate with the ultraviolet-curable pressure sensitive adhesive composition. The ultraviolet-curable pressure sensitive adhesive composition is capable of retaining ultraviolet curing properties even if the ultraviolet-curable pressure sensitive adhesive sheet is brought into contact with wash water for a long period of time.

Abstract: A pressure sensitive adhesive sheet for wafer sticking, comprising a base of polyvinyl chloride containing a plasticizer and, superimposed thereon, an energy radiation curable pressure sensitive adhesive layer of vinyl acetate copolymer, the energy radiation curable pressure sensitive adhesive layer, before exposure to energy radiation, having an elastic modulus ranging from 4.0×104 to 5.0×106 Pa at 50° C. The use of this pressure sensitive adhesive sheet for wafer sticking enables inhibiting the vibration of wafer at the time of dicing of the wafer so that chipping of the wafer can be minimized.

Abstract: Disclosed is an ultraviolet-curable pressure sensitive adhesive composition comprising an ultraviolet-curable pressure sensitive adhesive component and a phosphorus type photopolymerization initiator. Also disclosed is an ultraviolet-curable pressure sensitive adhesive sheet obtained by coating a substrate with the ultraviolet-curable pressure sensitive adhesive composition. The ultraviolet-curable pressure sensitive adhesive composition is capable of retaining ultraviolet curing properties even if the ultraviolet-curable pressure sensitive adhesive sheet is brought into contact with wash water for a long period of time.

Abstract: A pressure sensitive adhesive sheet for wafer sticking, comprising a base of polyvinyl chloride containing a plasticizer and, superimposed thereon, an energy radiation curable pressure sensitive adhesive layer, the energy radiation curable pressure sensitive adhesive layer, before exposure to energy radiation, having an elastic modulus ranging from 4.0×104 to 5.0×106 Pa at 50° C. The use of this pressure sensitive adhesive sheet for wafer sticking enables inhibiting the vibration of wafer at the time of dicing of the wafer so that chipping of the wafer can be minimized.

Abstract: A process for producing a chip, comprising the steps of: attaching an object to be diced on a pressure sensitive adhesive sheet comprising at least one layer of shrinkable film and a pressure sensitive adhesive layer; dicing the object into chips, and shrinking the shrinkable film to thereby reduce an area in which the chips are in contact with the pressure sensitive adhesive. In this process, chips of small thickness and large area can easily be picked up without the need to use a thrust needle in the chip pickup step.

Abstract: A process for producing a chip, comprising the steps of:a attaching an object to be diced on a pressure sensitive adhesive sheet comprising at least one layer of shrinkable film and a pressure sensitive adhesive layer;dicing the object into chips, andshrinking the shrinkable film to thereby reduce an area in which the chips are in contact with the pressure sensitive adhesive. In this process, chips of small thickness and large area can easily be picked up without the need to use a thrust needle in the chip pickup step.

Abstract: A pressure sensitive adhesive composition is disclosed which comprises an acrylic copolymer (A), an energy beam polymerizable urethane acrylate oligomer (B) and an energy beam polymerizable compound having one acryloyl group or methacryloyl group in each molecule thereof (C). This composition is preferred to further contain a plasticizer (D), a crosslinking agent (E) and/or a photopolymerization initiator (F) according to necessity. The pressure sensitive adhesive composition has satisfactory pressure sensitive adherence and initial adhesion before the irradiation with energy beam and the adhesive strength thereof is sharply reduced with maintaining the rubber elasticity after the irradiation with energy beam. Further, the pressure sensitive adhesive composition ensures excellent chip alignability in the expanding step subsequent to dicing.