The effects of substrate composition on thick film circuit reliability

The print and fire processing of thick film circuits ensures that there will always be some degree of chemical interaction between the film and the substrate, because all common substrate materials are soluble to some degree in the glass used in thick film inks. This interaction is primarily responsible for the development of adhesion between the thick film resistor and the substrate. By virtue of the resistor-substrate interaction, the composition of the glass is changed, and as a consequence all of the physical properties of the glass will change to some extent. This research program is directed toward the determination of the effects of the major constituent, common additives, and impurities in alumina substrates on the kinetics of microstructure development, electrical characteristics and the adhesion of thick film resistors.