A new light-weight electronic packaging technology based on spray-formed silicon-aluminium

There is a growing need to replace kovar, the established material used for packaging microwave hybrid circuitry, with substitutes which are lighter, stiffer and offer superior heat-sinking. Novel, isotropic-grained silicon-aluminium (Si-Al) alloys, high in silicon and prepared by the Osprey spray deposition technique satisfy these application requirements. Si-Al alloys have the additional merits of being non-toxic and relatively easy to machine and electroplate. Demonstrator microwave amplifier modules designed for space and terrestrial communication applications have been produced employing Si-Al packages and these have been successfully tested. The fabrication technologies that has been developed for this type of application are described. Other promising electronic applications for the new Si-AI alloys include opto-electronic modules and microwave waveguide components.