Wolfgang Schmitt

Pressureless low temperature sintering paste for NiAu PCB substrate

Conductive adhesive has been one of the popular choices for die attachment on PCB NiAu substrate. However, typical conductive adhesive has the lowest thermal and electrical conductivity among all die attach material. Consideration of silver sinter paste for NiAu PCB substrate is on the raise due to several of its advantages. Silver sinter paste is one of the key solution to the increasing demand for high thermal and reliable devices. It is also lead free and halogen free which is very much in line with the future environmental requirement of the microelectronic industry. There has been much work developed for pressure sinter paste and pressure-less sinter using higher sintering temperature of at least 230°C in the power module and power MOSFET segment. There are also reported work on low temperature, pressure-less sinter paste using nano-scale silver. In this paper, we report a low temperature silver sinter paste using micron scale silver that can be sintered at 200°C suitable for NiAu surface. 200°C sintering temperature would be favorable (but is not limited to) to PCB substrate as it minimize the risk of epoxy laminate decomposition during the long sintering profile. In this study, the general properties and thermal performance of this paste would be reviewed. In addition, the reliability performance of this silver sinter paste will also be share.

Properties of new solder paste system with ultra low residue for Die Attach and DCB

Since the beginning of the SMT process solder pastes have been developed and manufactured on the basis of resins/rosins. Due to problems caused by residues in the SMT and Semiconductor applications it was decided to develop an ultra low residue solder paste.