Considerations and Options for High Temperature Die Attach

Abstract

Development of electronics that can withstand temperatures ranging from 200oC up to 600oC is a growing research area. More electronic aircraft, space exploration and in engine automotive electronics are some examples of these research areas. As these operating temperatures rise so does the need for electronics packages that can handle these temperature ranges. A major aspect of this packaging is die attachment. There are currently two main metallurgy options proposed for high temperature die attachment. One is silver based metallurgies and the other is gold based metallurgies. Silver at high temperatures in the presence of an electric field will migrate between electrodes. This presents a major risk when using silver as a die attachment material for high temperature electronics. Part of the work presented here looks at silver’s migration characteristics and highlights the potential risks involved when using silver as a die attach material. Gold does not suffer from the same problem of migration as silver and therefore is a better choice for high temperature die attachment. Several gold based metallurgies have been used for die attachment. One other very useful feature of gold is that gold will self diffuse at elevated temperature and pressure. The other work presented here investigates the use gold-gold diffusion to form an acceptable die attachment for high temperature devices.