Patent ID: 8034667

Claim:
A method for manufacturing semiconductor devices comprising a step in which a circuit substrate with a semiconductor chip mounted thereon is prepared; the circuit substrate is heated; and then the surface of a sealing resin layer in an unheated semiconductor sealing resin sheet is embedded in concavo-convex parts and gaps on the semiconductor-chip-mounted surface of the circuit substrate and the surface of the sealing resin layer is brought into contact with the surface of the circuit substrate and then the sealing resin layer is thermally cured to seal the semiconductor chip, wherein the semiconductor sealing resin sheet is composed of a supporting sheet and the sealing resin layer releasably laminated on the supporting sheet, wherein the sealing resin layer has a thermosetting property, the sealing resin layer before thermosetting has an elastic modulus of 1.0×10 3 to 1.0×10 4 Pa and a melt viscosity at 120° C. of 100 to 200 Pa·s, and the time required for the melt viscosity to reach its minimum value is 60 sec or less when the sealing resin layer before thermosetting is kept at a constant temperature of 120° C.