A hermetically sealed feedthrough filter assembly is attachable to an active implantable medical device and includes an insulator substrate assembly and a feedthrough filter capacitor disposed on a device side. A conductive leadwire has a proximal leadwire end extending to a distal leadwire end, wherein the proximal leadwire end is connectable to electronics internal to the AIMD. The distal leadwire end is disposed at least partially through a first passageway of the feedthrough filter capacitor and is in contact with, adjacent to or near a device side conductive fill. A first electrically conductive material makes a three-way electrically connection that electrically connects the device side conductive fill to an internal metallization of the feedthrough filter capacitor and to the distal leadwire end. A second electrically conductive material electrically connects an external metallization of the feedthrough filter capacitor to a ferrule or an AIMD housing.