Resolving No Solder Joint Issue Thru Understanding of Basic Principle in Solder and Heat Transfer

Abstract

Cu clip is one of the interconnect technology used in semiconductor packaging. It has a distinct advantage over Au and Cu wire as well as Al ribbon electrical performance. In a standard SO8 package the cu clip electrical resistance is less than 10% of eight 2.0mil Au wires. The better electrical performance coupled with the increase in Au prices, Cu clip has become more and more attractive for MOSFET discrete product like DC-DC converter. This paper discusses the one of the challenges faced during the Cu clip development for 8MLPD3.3x3.3, no solder joint. Thru the understanding of solder properties and basic principle of heat transfer the issued was resolved through solder reflow oven modification and profile optimization.