Joining methods in electronics packaging: Sintered silver and eutectic bonding

Joining and interconnect techniques play vital roles in electronics packaging. Some take advantage of diffusion below melting temperature, ideal for solid-state bonding, soldering, die-attach and sealing applications. A silver paste sintered below 300°C was evaluated as a potential die-attach material. While silver epoxy is a common die-attach adhesive, non-epoxy materials are needed for high-power and high-temperature packaging. Sintering behavior was investigated by observing microstructure developments versus temperature to relate its impact on thermal conductivity. Further, silver migration potential was assessed under high temperature, voltage, and humidity conditions.;The eutectic bonding process is fundamental for environmentally-sensitive devices that require a quality hermetic seal for their encapsulation. An experimental eutectic composition of aluminum and germanium was tested to investigate the resulting bond in terms of observable phase mixing after a successive procedure of diffusion, melting, and solidification. Additionally, the ensuing bond strength was measured via repeated pull testing of several sample coupons.