Method for reworking metal layers on integrated circuit bond pads

Abstract

A method for reworking integrated circuit (IC) wafers having copper-metallized bond pads exposed in protective overcoat openings and one or more bondable metal layers deposited onto the bond pads by a technology which may produce some parts with off-spec or missing depositions. After identifying the wafer with off-spec metal layers, a layer of glass buffer is deposited over those wafers, which also fill any missing depositions at least partially. The glass-covered surface is then chemically-mechanically polished until the off-spec metal layers and at least portion of the protective overcoat are removed, without damaging the copper metallization. Finally, a fresh layer of protective overcoat is deposited, selectively opened to expose the bond pads, and provided anew with one or more bondable metal layers. The slurry for the chemical-mechanical polishing contains oxidizing or hydroxylating agents as well as mechanical polishing components for metals which are not readily oxidized. In order to minimize undesired scratches of the underlying copper or dielectric layers, a combination of buffers and soft poromeric pads is used. Alternatively, organic buffer layers can be used instead of the glass buffer.

Dependencies are inferred from the claim text.