INNOVATIVE THIN FILM TECHNIQUES TO ELIMINATE FAULTY WIRE BONDS AND IMPROVE HIGH FREQUENCY CIRCUIT DENSITIES

摘要

Thin film interconnects are a standard circuit technology used in high frequency design components and subsystems where transmission line widths of .005" and under are critical to performance as well as high power applications where thermal conductivity is of concern and materials such as beryllium oxide and aluminum nitride must be considered. This unique technology is employed in a variety of military and homeland security platforms from radar to EW and counter-measure applications, to missile and armament receivers and sensors. Thin film is traditionally recognized as a single plane technology, where design engineers typically use wire bonds with eutectic solder or conductive epoxies to create interconnects from thin film circuits to various passive and active components and semiconduc- tor devices in their systems. Engineers also use air bridges at some junctions. Although these methods are mature, and their performance over time predictable, industry sources suggest they are susceptible to failure, high assembly and tuning costs, and performance inconsistency due to the fragility of wire bonds, particularly as one considers that today's circuits have tiny bonding pads and require very short bond loops, and that it usually takes an operator with special skills to make those wire bonds. This is especially true of the center wire bonds.