FEA study on electrical interconnects for a power QFN package

Abstract

This paper presents the results of a numerical analysis on the electrical interconnect options of a Power QFN (PQFN) package, to explore and compare the RDS(ON) performance at DC condition. The modeling involves the PQFN 5mm × 6mm package which initially uses Aluminum wire bonds for interconnection. Competition in the market in terms of better electrical performance packages challenge semiconductor companies to venture into new technology, innovation, process, wafer fabrication, package design changes. For the PQFN, apart from having a thin die with low specific RDS(ON), it is necessary to choose an interconnect which is also electrically efficient. Among the choices aside from the traditional Aluminum round wires are Aluminum ribbon bonding and Cu clip bonding. The comparison is purely based on the electrical performance and the study does not include the cost factors and other material related effects such as stress performance, etc. A commercial FEA code, ANSYS®, is utilized in this study while Solidworks® is used for CAD.