To provide a pressure sensitive adhesive sheet which enables to regulate immobilization force of a wafer at dicing and delamination at picking up, enables to stick an adhesive agent for semiconductor elements and a film for a dicing process collectively, and has high adhesiveness and excellent reflow crack resistance, a method for producing a semiconductor device through a simple process, and a semiconductor device which is excellent in soldering reflow crack resistance and reliability.

The pressure sensitive adhesive sheet comprises a base material layer and a pressure sensitive adhesive layer containing (A) an energy ray- curable component and (B) a heat-curable component, wherein the pressure sensitive adhesive layer has an elastic modulus of 10 MPa or less at 250°C and has a water absorption of 1.5% by volume or less after it is irradiated by a necessary amount of energy ray to immobilize to semiconductor elements and then heated to cure. The semiconductor device is produced with the pressure sensitive adhesive sheet.