Conductive via fill inks for ceramic multilayer circuit boards on support substrates

Abstract

Conductive via fill inks for green tapes to be stacked and bonded to a support substrate, the glass used for the green tape having a firing temperature from 850.degree.-950.degree. C., wherein the glass used for the via fill ink has a glass transition temperature that is higher than that of the glass used to make the green tape, preferably does not crystallize at the maximum firing temperature of the green tape and comprises from 30-75 percent by volume of the glass-conductive metal powder mixture of the via fill ink. These conductive via fill inks will not shrink until the green tape shrinkage has commenced during firing of the composite circuit board and they will flow slightly during firing, forming good bonds to the glass in the walls of the vias, thereby ensuring good integrity of the vias and good connections to the circuitry on the fired ceramic multilayer circuit board.

Dependencies are inferred from the claim text.