Electrically conductive vias through ceramic substrates - are made by drawing metal from tracks into holes by capillary action using filling of holes by suitable powder

摘要

Electrically conductive vias (5) are formed in ceramic substrates (1) which have conductive tracks and/or contact regions (2,3) on both surfaces which have been attached by direct bonding. The feature of the process is that the holes for the vias are filled with a powder (4), which pref. is a chemical cpd. of the metal, which has been direct bonded and the reactive ambient gas. The powder is pref. formed into a paste, which contains pref. Cu-hydroxide as a binder. Especially claimed is the use of Cu for the conductive tracks (2,3) and Cu, Cu-oxide or Cu-hydroxide as the powder filing (4). USE/ADVANTAGE - The process forms reliable and conductive connections which contact the metallisation on both surfaces and are attached to the walls of the via. The mechanical and electrical properties are good and allow multilayer boards to be mfd. in a single operation.