Fabricating an RF filter on a semiconductor package using selective seeding

Abstract

A method of fabricating an RF filter on a semiconductor package comprises forming a first dielectric buildup film. A second dielectric buildup film is formed over the first dielectric buildup film, the second dielectric buildup film comprising a dielectric material that contains a metallization catalyst, wherein the dielectric material comprises one of an epoxy-polymer blend dielectric material, silicon dioxide and silicon nitride, and a low-k dielectric. A trench is formed in the second dielectric buildup film with laser ablation, wherein the laser ablation selectively activates sidewalls of the trench for electroless metal deposition. A metal selectively is plated to sidewalls of the trench based at least in part on the metallization catalyst and immersion in an electroless solution. A low-loss buildup film is formed over the metal that substantially fills the trench.

Dependencies are inferred from the claim text.