Patent ID: 8337656

Claim:
A pressure-sensitive adhesive sheet comprising a base layer A, a pressure-sensitive adhesive layer A, a base layer B, and a pressure-sensitive adhesive layer B as arranged in this order, wherein the base layer A is a base layer having such a Young's modulus at 25° C., a Young's modulus at 80° C., and a thickness that the product of the Young's modulus at 25° C. and the thickness is 1.0×10 5 to 4.0×10 5 N/m and the product of the Young's modulus at 80° C. and the thickness is 2.8×10 5 N/m or less; wherein the pressure-sensitive adhesive layer A is a pressure-sensitive adhesive layer having a shear modulus at 80° C. of 0.2 MPa or less; wherein the base layer B has such a thickness and a Young's modulus at 25° C. that the product of the Young's modulus at 25° C. and the thickness is smaller than the product, of the base layer A, of the Young's modulus at 25° C. and the thickness, and wherein the base layer B is a heat-shrinkable base layer having, upon 80° C. heating, a shrink percentage in a main shrinkage direction of 20% or more and a shrink percentage in a direction perpendicular to the main shrinkage direction of 20% or more; and wherein the pressure-sensitive adhesive layer B is a pressure-sensitive adhesive layer having a Young's modulus at 80° C. of 10 MPa or more and having an adhesive strength to a silicon wafer (180-degree peel at a tensile speed of 300 mm/min) of 0.2 N/10 mm or less.