The use of thick print copper and silver conductors for power applications

Thick printing Cu and Ag conductors have been developed specifically for use in power applications where excellent printing, thermal, electrical, wire bonding and soldering properties are prerequisite. Efficient thermal management can require fired films on alumina in excess of 150μm and often printed in large areas. In some designs the thickness of mounting pads alone for bare silicon dies may need to be built up locally. This approach enables a single substrate to comprise both thinner printed, dense circuitry for signal control and thick device mounting pads for efficient thermal management. The flexibility of thickness control, through hole connections and the ability to incorporate printed resistors using standard thick film processing can offer solutions which complement the other substrate technologies in many applications. This paper describes the advancements made in optimizing the performance of thick printing copper and silver conductors designed for use in power applications and their role in this demanding technology. The features of the materials, process guidelines, and performance characteristics will be discussed.