Direct-bonded aluminum on aluminum nitride substrates by transient liquid phase bonding

Abstract

A new bonding process has been developed for producing direct-bonded aluminum (DBA) substrates using aluminum nitride (AlN). A transient eutectic liquid phase forms in aluminum–X (X = silicon, germanium, silver, or copper) systems at the interface between the aluminum foil and the AlN substrate. The aluminum–X liquid phase transiently contacts the AlN substrate prior to isothermal solidification by diffusion of the element X into the aluminum foil. We have prepared DBA substrates using this process and demonstrated that they are highly stable after thermal cycling testing.