ChemInform Abstract: Effects of Silver Dissolved in Eutectic Gold‐Silicon Solder on Silicon Devices.

Abstract

366ChemInform Abstract In a die bond system using eutectic Au-Si solder, stress in the die tends to increase when Au is replaced by Ag as a plating material on Cu alloy leadframes. This increase in stress is mainly caused by Ag dissolution into the Au-Si solder. The freezing point of the eutectic Au-Si solder increases with increasing Ag content. The dissolution of Ag increases with an increase in the bonding temp., leading to an increase in solder hardness. The experimental results demonstrate that the bonding to a Ag-plated leadframe using Au-Si solder at a temp. much higher than the eutectic temp. induces larger residual thermal stress in the chip and causes lower performance of devices during temp. cycling tests.