Reverse tone mask method for post-CMP elimination of copper overburden

Abstract

A novel reverse-tone mask method which is capable of eliminating metal overburden humps in a metal layer electroplated onto a substrate, is disclosed. Typically, the method includes providing a masking layer on a metal layer such as copper previously electroplated onto a substrate; depositing a photoresist layer on the masking layer; patterning the photoresist layer according to the size and location of the largest metal overburden humps in the metal layer; exposing the overburden humps by etching the masking layer according to the patterned photoresist layer; stripping the photoresist layer from the masking layer; subjecting the metal overburden humps to a first CMP or reverse electroplating process; removing the masking layer from the metal layer; and subjecting the metal layer to a second CMP or reverse electroplating process.

Dependencies are inferred from the claim text.