Lead frame for semiconductor device

摘要

The invention concerns a resin molded lead frame for semiconductor devices. The lead frame comprises a die pad 24 on which a die is mounted, inner leads 26 which are electrically connected to bonding pads of the die by a bonding wire 23 and outer leads 28 which are electrically connectable to a printed wiring board. The die pad 24 and inner leads 26 are encased within a resin molding 20. The lead frame is made of a metal having a similar thermal expansion coefficient to that of the wiring area of the printed wiring board, and the surfaces of the die pad 24 and inner leads 26 of the lead frame are covered at least partially with a metal cladding. The outer leads 28 then have a thermal expansion coefficient which is similar to that of the printed wiring board thereby making it possible to prevent or reduce solder joint cracks between the outer leads 28 and the land of the printed wire board and to improve reliability of surface mounting connections.