A Drop-in Die-Attach Solution for the High Temperature Lead-Free BiAgX Solder Paste System (original) (raw)

In the current work, a mixed powder BiAgX solder paste system with the melting temperature above 260°C and comparable, or better, reliability to the high lead-containing solders has been studied. The mixed powder solder paste system is composed of a high-melting first alloy solder powder as a majority and the additive solder powder as a minority. The additive solder is designed to react aggressively with various surface finish materials before, or together with, the melting of the majority solder to form a controllable IMC layer. The IMC layer of the mixed powder system is controllable by the species and quantity of the additive solder, and it is observed to be insensitive to thermal aging and thermal cycling in current tests, while the high lead-containing solders show a considerable increase in IMC layer thickness. Microstructure investigation shows that the fishbone shaped IMC layer interlocks with the bonding interface between solder and components. Both micron-sized and nano-si...