To improve workability, adhesive property, insulation reliability and durability by a method wherein one or more kinds of resin and thermosetting resin, having an amide group and/or an imide group, are contained as the essential component of an adhesive material composition.
A bonding agent solution is formed by dimer acid polyamide, epoxy resin, 4,4'-diaminodiphenylsulfone, phenol resin and triphenylphosphine, in the prescribed mixing ratio, and ethanol/toluene mixed solution. This bonding agent solution is applied to a polyethylene terephthalate film and the applied solution is dried up. On the other hand, an adhesive layer is formed in the same manner as above excepting the use of polyethylene terephthalate and silicone mold releasing agent having low stripping force. Then, an adhesive sheet for semiconductor device is formed by laminating two sheets of the above- mentioned film, formed by putting adhesive surfaces together, and a pure copper plate, having an adhesive layer, is obtained by laminating the pure copper plates.