Manufacturing methods for microwave circuits

Two processes were investigated to manufacture microwave circuit films on hard dielectric substrates, and each proved superior when compared to the conventional wet chemical etching process. Ion beam milling was developed at the Microwave Division of Sanders Associates, Inc., and its high quality low cost capability instigated replacement of the wet chemical etch process. Up-plating was developed at the Microelectronics Center of the Naval Research Laboratories. Both methods demonstrate substantial improvements in the dimensional film definition achieved in manufacturing microwave circuits.