Pressure-assisted low-temperature sintering of silver paste as an alternative die-attach solution to solder reflow

Pressure-assisted low-temperature sintering of silver paste is shown to be a viable alternative to solder reflow as a die-attachment solution. A quasihydrostatic pressure is used to lower the sintering temperature. The effect of parameters such as temperature and pressure are investigated. Characterization of the silver-attached samples shows a significant improvement in electrical conductivity, thermal conductivity and mechanical strength of the joint. Given that silver deforms with little accumulation of inelastic strains, and given the absence of large voids in the attachment layer, it is also expected that the joint to be more resistant to fatigue failure than a solder attached junction. Due to the high melting temperature of silver, this alternative process is also suitable for high temperature packages.