Patent ID: 7521295

Claim:
A method of manufacturing a lead frame, comprising the steps of: mounting a first dry film on front and back surfaces of an elongate metal plate, exposing the metal plate and the first dry film using a first mask having predetermined shading patterns, and then removing by development only portions of the first dry film on which said portions are necessary to be plated, plating nickel, palladium and gold in turn on metal plate portions appearing by removing the first dry film, stripping the first dry film, mounting a second dry film on the plated metal plate, exposing the metal plate and the second dry film using a second mask having predetermined shading patterns, and then developing the metal plate, spraying etching liquid on the metal plate to carry out etching, stripping the second dry film, and cutting the metal plate in a predetermined length and therein plate only surfaces of the portion for mounting thereon a semiconductor element and portions to which gold wires are bonded.