PROCEDE D'ELIMINATION DES COURTS-CIRCUITS DE CROISEMENT DE DEUXCONDUCTEURS A DES NIVEAUX DIFFERENTS

摘要

1369690 Printed circuits WESTERN ELECTRIC CO Inc 21 Dec 1971 [21 Dec 1970] 59326/71 Heading H1R A method of forming thin film circuitry, including a pattern of thin film material and a crossover conductor, on a substrate includes a process wherein material between said pattern and said crossover conductor generates a gas causing the cross-over conductor to bend outwards from the substrate. A short circuit between a gold beam crossover conductor, supported by gold pillars, and a gold crossunder conductor, formed on a bonding layer of titanium and platinum, is removed by first heating the ceramic substrate in air to between 250- 450‹ C. for 1-3 minutes before allowing to cool to room temperature. The substrate is then placed in a closed chamber evacuated to at least 50 torr. and a slurry of finely divided ammonium bicarbonate in water and an 8 molar solution of acetic acid are introduced on to the surface of the substrate resulting in the vigorous evolution of carbon dioxide which bows the gold beams upward and flushes any debris from the space beneath. Other specified substances which liberate gas in sufficient quantities may be used or alternatively a liquid or polymer material which contains foaming agents may be activated to expand and bend the crossover conductor. To remove any slender threads which may remain lodged between the crossover and the pattern the substrate is etched with a dilute aqua regia gold-etch.