Abstract: A method of fabricating an electronic package having an organic substrate. The substrate is formed of fiberglass and epoxy. In order to additively circuitize the electronic package substrate, an organic polyelectrolyte is deposited onto the organic substrate. A colloidal palladium-tin seed layer is deposited atop the organic polyelectrolyte. This is followed by depositing a photoimageable polymer atop the seed layer, and photolithographically patterning the photoimageable polymer to uncover portions of the seed. layer. The uncovered portions of the seed layer are catalytic to the electroless deposition of copper. In this way a conductive layer of copper is deposited atop the uncovered seed layer. The organic polyelectrolyte is deposited from an aqueous solution at the pH appropriate for the desired seed catalyst coating, depending on the ionizable character of the particular polyelectrolyte employed.

Abstract: A method of fabricating an electronic package having an organic substrate. The substrate is formed of fiberglass and epoxy. In order to additively circuitize the electronic package substrate, an organic polyelectrolyte is deposited onto the organic substrate. A colloidal palladium-tin seed layer is deposited atop the organic polyelectrolyte. This is followed by depositing a photoimagable polymer atop the seed layer, and photolithographically patterning the photoimagable polymer to uncover portions of the seed layer. The uncovered portions of the seed layer are catalytic to the electroless deposition of copper. In this way a conductive layer of copper is deposited atop the uncovered seed layer. The organic polyelectrolyte is deposited from an aqueous solution at the pH appropriate for the desired seed catalyst coating, depending on the ionizable character of the particular polyelectrolyte employed.

Abstract: A process for making a circuitized substrate is defined wherein the substrate is treated with two different, e.g., additive and subtractive, metallization processes. The process is thus able to effectively produce substrates including conductive features, e. g., high density circuit lines and chip heat-sinking pads, of two different degrees of resolution in a cost effective and expeditious manner. The resulting product is also defined.

Abstract: A process for making a circuitized substrate is defined wherein the substrate is treated with two different, e.g., additive and subtractive, metallization processes. The process is thus able to effectively produce substrates including conductive features, e.g., high density circuit lines and chip heat-sinking pads, of two different degrees of resolution in a cost effective and expeditious manner. The resulting product is also defined.