Bonding Conductors to Microelectronic Devices and Packages
Original Publication Date: 1985-May-01
Included in the Prior Art Database: 2005-Feb-18
Conductors are bonded to microelectronic devices by combining two specific metallic materials at low temperature to form a third relatively high melting point material where the metals are a combination of metals selected from groups such as Au-Cu-Sn or Au-Ni-Sn-Cu. This method involves the layering of Au, Sn and other metals which melt together at low temperatures to form an alloy which melts at high temperatures. A layer of gold and a layer of tin are laminated prior to bonding. When they are heated, the tin melts first, producing a low melting point gold-tin liquid which reacts with the remaining gold to form a high melting point gold-rich alloy.