Method for fabricating metal interconnect structure

摘要

A method for fabricating a metal interconnect structure. A first insulating layer and a second insulating layer with a low dielectric constant are formed on a substrate in sequence. An opening is formed in the second insulating layer. A compact and high density third insulating layer is formed on the second insulating layer and in the opening to protect the second insulating layer from being damaged in a subsequent process for removing a photo-resist layer. A contact window is then formed in the third insulating layer at a bottom of the opening and the first insulating layer, so that a dual damascene opening is formed. The dual damascene opening is filled with metal with low resistivity to form the metal interconnect.