Highly reliable nickel-tin transient liquid phase bonding technology for high temperature operational power electronics in electrified vehicles

This paper presents an approach to nickel-tin transient liquid phase (TLP) bonding that provides high reliability for high temperature operational power electronics in electrified vehicles. The need for automotive power electronics to operate at high temperature presents significant challenges in terms of the packaging and bonding technology used. Transient liquid phase (TLP) bonding is one attachment approach that addresses these challenges. The Ni/Sn TLP bonding process exhibits a number of desirable characteristics, including a good CTE match with silicon and silicon carbide, popularity in conventional power electronics, low cost, and uniform alloy formation. The work herein presents a Ni/Sn TLP bonding technology (ready for high temperature operation up to 200°C) as applied to large size silicon power devices (12 mm × 9 mm). Analysis indicates that the resulting bondline is uniformly composed of Ni₃Sn₄ alloy throughout. This bonding approach has exhibited excellent reliability for bonded devices after 1000 thermal cycles from -40 to 200°C.