Lead frame having a die pad with metal foil layers attached to the surfaces

摘要

In a lead frame material made of a strip of copper or copper alloy sheet for use in resin packages in which semiconductor chips are mounted to and resin-sealed in island portions of a lead frame fabricated from a strip of substrate material, the lead frame material includes selective spot-clad material in which metal foils of low thermal expansion, each of a predetermined size, are roll-bonded and arranged at a predetermined interval to respective positions to be formed with island portions in the longitudinal direction of the substrate material, either on the surface where the semiconductor chips are not to be mounted or on both the surface where the semiconductor chips are to be mounted and on the opposite side. Damage to the chips such as warping or peeling can be prevented during heating upon mounting them.