Patent ID: 7214424
Filing Date: 2007-05-08
Classification: C09J,H01L,Y10S,Y10T

Abstract:
1. A heat-peelable pressure-sensitive adhesive sheet comprising a substrate, a heat-expandable layer which contains heat-expandable microspheres and expands upon heating, formed on at least one side of the substrate, and a non-heat-expandable pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive formed on the heat-expandable layer, wherein when the heat-peelable pressure-sensitive sheet is adhered to a semiconductor silicon wafer and then peeled from the wafer by heating, an amount of organic contamination on the surface of the semiconductor silicon wafer Δc is 50 or less, wherein the pressure-sensitive adhesive in the non-heat-expandable pressure-sensitive adhesive layer comprises a polymer, containing (i) a low molecular weight component having a molecular weight of 100,000 or less in an amount of 15% by weight or less, based on the weight of the polymer, and (ii) a component having a molecular weight of greater than 100,000, wherein the polymer has a conversion of 80.5% to 97% after polymerization, and wherein the non-heat-expandable pressure-sensitive adhesive layer has a thickness of 20 μm or less.