Leadframes for improved moisture reliability and enhanced solderability of semiconductor devices

摘要

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.