Manufacturing processes for hybrid microcircuits containing vias

Manufacturing processes were developed for making holes in alumina substrates, metallizing substrates on both sides and through vias, dry film photolithographing 6 micrometers thick gold to 5 mil (127 micrometers) line widths and spacing, and determining via quality and acceptance. The techniques developed produced vias with low resistance characteristics. Vias have been produced which exhibit through-hole resistances of less than 10 m omega and are acceptable for radio frequency of logic circuit application. Sample parts have been fabricated and evaluated on both test substrates and production substrates to prove-in the new techniques. An orbital planetary system which metallizes substrates on both sides and through the vias simultaneously is being characterized.