A high entropy alloy as very low melting point solder for advanced electronic packaging

TL;DR

This paper investigates a SnBiInZn high entropy alloy as a low melting point solder suitable for advanced electronic packaging, demonstrating its favorable wetting properties and slow intermetallic growth at around 80°C.

Contribution

It introduces a novel high entropy alloy solder with an ultra-low melting point and detailed analysis of its wetting and interfacial properties for electronic applications.

Findings

Melting point around 80°C

Wetting angle about 52° after reflow at 100°C

Interfacial IMC growth is slow with low activation energy

Abstract

SnBiInZn based high entropy alloy (HEA) was studied as a low reflow temperature solder with melting point around 80 oC. The wetting angle is about 52o after reflow at 100 oC for 10 min. The interfacial intermetallic compound (IMC) growth kinetics was measured to be ripening-control with a low activation energy about 18.0 kJ/mol, however, the interfacial reaction rate is very slow, leading to the formation of a very thin IMC layer. The low melting point HEA solder has potential applications in advanced electronic packaging technology, especially for bio-medical devices.