MANUFACTURE OF LEAD FRAME FOR SEMICONDUCTOR DEVICE

PURPOSE:To obtain, at low cost, a lead frame making it possible to increase reliability by a method wherein an Au coat is formed directly on a part to be a die pad element and/or an outer lead element and, after the exfoliation of a resist, the part is punched to be shaped in the main body of the lead frame by pressing. CONSTITUTION:An organic-removed-type resist being used, a resist film is formed only on a part to be an inner lead element, and the base material thus prepared is passed through an NaOH water solution to remove Al on an exposed unnecessary part. The part of the obtained base material having an Al coat and the resist film partly, other than a die pad element and an outer lead element, is covered with a rubber mask, subjected to degreasing and surface etching and then plated with Au continuously. Thereafter the material is immersed in an organic solvent to remove the resist and is formed into a lead frame in a prescribed shape by press punching. The lead frame thus obtained has a structure wherein an Au coat 2a is built up on the die pad element of the main body 1 of the lead frame, an Au coat 2b on the outer lead element and the Al coat 3 on the inner lead element 3 respectively in a direct manner.