Process for making metalised openings in dielectric substrates containing conductive and/or resistive pathways in thin film, especially for fine lines

摘要

A process is described for making metalised holes in dielectric substrates containing conductive and/or resistive pathways belonging to hybrid thin film circuits for microwave applications. The process comprises, in succession, the phases of depositing, on the front surface of the dielectric, superimposed layers of TaN, Ti and Pd; photomasking and depositing of gold along predetermined pathways; removal of TaN, Ti and Pd outside of said pathways; photoengraving of Au, Pd and Ti at the location of the resistors; drilling in zones free of metal; depositing of a negative photoresist on the front side, photomasking of circular areas superimposed on the holes and partially on the conductive pathways; development; vacuum sputtering of Ti and Pd on the front side and back side; heating of the photoresist and of the metals on top of it; repetition of the photoresist on the front side; adding of Au by galvanic means; elimination of the residual photoresist. IMAGE