Method of removing flash from a semiconductor leadframe using coated leadframe and solvent

A process for producing a semiconductor device which is received in a concavity of a core-box resin molded item, said process comprising the steps of:

• coating a lead frame on its portions expected to be in non-contact with said core-box resin molded item with an organic high molecular substance having a melting or softening point higher than the molding temperature of a resin constituting said one-box resin molded item and soluble in a solvent which does not dissolve said core-box resin molded item, the organic high molecular substance being selected from the group consisting or cellulose derivatives and epoxy resins;
• placing the thus coated lead frame in position within a mold and injecting said resin into said mold, thereby obtaining the core-box resin molded item integrated with the lead frame;
• immersing the lead frame of the core-box resin molded item into said solvent to dissolve said organic high molecular substance coated on said lead frame;
• die-bonding said semiconductor element to an island of said lead frame and then wire bonding electrodes of said semiconductor element to said lead frame;
• and
• fusion-bonding a covering member of said core-box resin molded item to seal hermetically the whole concavity of said core-box resin molded item.