Patent attributes
A two-step via cleaning process that removes metal polymer and oxide polymer residues from a via with substantially no damage to the via or underlying structures on a semiconductor substrate. The via is formed through a dielectric layer and a barrier layer that are disposed over a metal-containing trace disposed on a semiconductor substrate. Sidewalls of the via may be coated with a residue layer including a distinct oxide polymer component and a distinct metal polymer component. The two-step via cleaning process comprises subjecting the residue layer to a nitric acid dip that removes the metal polymer component to expose the oxide polymer component. The oxide polymer component is then subjected to a phosphoric acid dip that removes the oxide polymer component. The oxide polymer and metal polymer residues may also be removed during the fabrication of the via by removing them directly after their respective formations.
