Surface Treatments and Bondability of Copper Thick Film Circuits

Crucial issues in using copper thick film microcircuits, namely, surface treatment and bondability, are addressed. A multilayer multichip ceramic substrate package with copper thick film conductors was used for these experiments. Surface treatments for bondability specific to different types of bonding sites are discussed. Using a flip tape automated bonding (TAB) technology, the resultant bond interfaces were analyzed in the as-bonded as well as thermally aged conditions. Results indicate a metallurgically stable materials system which should exhibit long-term reliability. Specific recommendations on copper surface treatments and general guidelines on materials selection are made on the production of reliable copper thick film interconnections.