Microstructure and Composition of Au-Sn Eutectic Solder Electroplated from a Single Solution

Abstract

In this study, we produced Au-Sn alloy electroplated from a single solution and optimized the composition. The composition of electroplated Au-Sn alloy was Au-31.02 at.% Sn at the condition of 6 ms on -4 ms off pulse current, 50 and 10 mA/cm 2 . Results in XRD analysis showed that Au-Sn alloy electroplated at DC 10 mA/cm 2 had AuSn phase (ξ′) only and Au 5 Sn phase (δ) appeared with decreasing the pulsed current on time. Also micropatterned Au-Sn solder bump was produced by photolithography. Though it's composition of at.% Sn was not optimum, we tried to bond between Au-Sn solder bump and Si wafer that was coated with Ti (100 nm)/Au (300 nm).