Abstract: The present invention provides a two-component printable conductive composition comprising, as separate components, a metallic component comprising a high melting point (HMP) metal or metal alloy powder having a mean particle size below about 15 ?m; and a fluxing component comprising an organic acid and an organic solvent. The organic acid is characterized by having at least two carboxylic groups and a first logarithmic acid dissociation constant (p Ka1) of at most about 4. These two components are manufactured and stored separately and are mixed together shortly before the combined conductive composition is used for printing. Further provided is a kit comprising the two-component composition, wherein the metallic component and the fluxing component are disposed in separate containers.

Abstract: A sheet-fed system designed to print multilayer PCBs is introduced. The system consists of four main blocks; a drilling station, a patterning station, a stacking/bonding station, and a sintering zone. The substrate PCB is shuttled between these various stations, to have vias drilled, to be attached to stacks of previously-processed layers, to be covered with conductive paths by means of the aforementioned ink, and to have the ink sintered under a controlled temperature and atmosphere. Patterning is accomplished by means of a novel two-step method involving both high-temperature conductive elements, low-temperature conductive elements, and flux. Two such compositions are successively applied and individually sintered to form a single conductive path; the second application serves to fill the porosities of the first layer. By this method, a highly-conductive trace is obtained without requiring high temperatures, which in turn allows use of common substrates including polymers.