Abstract: Chips first packaging structures and methods of fabrication are presented which employ electroless metallizations. An electroless barrier metal is disposed over and in electrical contact with at least one aluminum contact pad of the chips first integrated circuit. The electroless barrier metal is a first electroless metal and is a different material than the at least one aluminum contact pad. An electroless interconnect metal is disposed above and electrically contacts the electroless barrier metal. The electroless interconnect metal is a second electroless metal, which is different from the first electroless metal. As an example, the electroless barrier metal comprises electroless nickel and the electroless interconnect metal comprises electroless copper.