High-Adhesion Thick-Film Gold Without Glass or Metal-Oxide Powder Additives

The problems of bonding gold to glass or ceramic are discussed. Glass-to-gold bonding is necessary to obtain the adhesion of gold conductors in thick- or thin-film circuits. The history of thick-film gold conductors is reviewed from the frit-bonded to the reactively bonded to the mixed-bonded system, Which is the current standard. A new different method of achieving gold thick-film adhesion is presented. This adhesion is caused by a molecular layer of cadmium and bismuth oxide on the surface of gold. The coating is Obtained during firing from base metal resinates contained in the ink vehicle. Such surface active ("surfactive") gold ink without frit or metal-oxide powder additives provides optimized adhesion and wire bondability when used as a top conductor in multilayer circuits.