High temperature storage performance for Au Sn diffusion soldering on Cu leadframe substrate

It has been reported that the microstructure of the Au20Sn solder was strongly affected by the dissolution of Cu in the reflow process. From this findings a study had been conducted but this time using a four layer stacked back side metallization using Au25Sn on Cu leadframe substrate on the effect of the inter metallic compound after long stoppages until 10 mins at die bonding tunnel with complete supply of 85%N
₂
15%H
₂
extended up to 2000hrs of High Temperature Storage at 175°C. The layer stacked was using ametal stack of Al400nm/Ti400nm/andNiV75nm/75Au25Sn 1200nm, the samples were then die bonded at 360° C using TO 263 LPL selective NiNiP leadframe.