A semiconductor device has a leadframe with a structure made of a base
metal (105), wherein the structure consists of a chip mount pad (302) and
a plurality of lead segments (303). Covering the base metal are,
consecutively, a continuous nickel layer (201) on the base metal, a layer
of palladium on the nickel, wherein the palladium layer (203) on the chip
side of the structure is thicker than the palladium layer (202) opposite
the chip, and a gold layer (204) on the palladium layer (202) opposite
the chip. A semiconductor chip (310) is attached to the chip mount pad
and conductive connections (312) span from the chip to the lead segments.
Polymeric encapsulation compound (320) covers the chip, the connections,
and portions of the lead segments, but leaves other segment portions
available for solder reflow attachment to external parts.