The introduction of semiconductor techniques and integrated circuits on silicon chips has stimulated a need for denser and smaller interconnection methods. This need has been met using the now common hybrid technologies of providing thin film conductors, resistors, and possibly capacitors on ceramic substrates with subsequent addition of applique devices. The thin film techniques and properties are well documented in the literature.1,2The thin film technology was chosen by Sandia in 1970 for use in high−reliability microcircuits. The basis of specific technologies selected and early production results have been described by Tapp and Wiley.3One set of technologies was chosen for detailed development studies; this set included alumina substrates with sputtered tantalum nitrate resistors and evaporated chromium−gold conductors.The basis for selection of a metallization system for production processing and the tribulations of instituting that system in a production line are briefly reviewed. The use of surface analytical techniques and complete R and D investigations for assuring good product are important for successful commercial processing of thin films. The success is evident in current production where the yield of the chromium−gold evaporation processing is 98% and of the subsequent thermocompression gold−gold bonding is 96%.3The chromium−gold evaporated metallization of 3 μ Au on 3 nm Cr on 99.5% alumina substrates provides a good conductor with resistivities from 3.0 to 4.0μΩ−cm. The major limitation of the system is diffusion of chromium to the Au surface. Deposition at elevated substrate temperatures of 300−400°C provides larger gold grains and appears to place the chromium in solution, minimizing the rapid grain boundary or surface diffusion.