Method for making integrated circuit capacitor including anchored plug

Abstract

A method for making an integrated circuit capacitor includes forming an interconnection line adjacent a substrate, forming a first dielectric layer on the interconnection line, forming a first opening in the first dielectric layer, and forming a second opening in the interconnection line aligned with the first opening and having an enlarged width portion greater than a width of the first opening. The method further includes filling the first and second openings with a conductive metal to define a metal plug having a body portion and an anchor portion adjacent lower portions of the first dielectric layer. The method also includes forming a trench in the first dielectric layer adjacent the body portion of the metal plug, forming a first electrode lining the trench and contacting the metal plug, forming a second dielectric layer on the first electrode, and forming a second electrode on the second dielectric layer. Because the metal plug is anchored, a depth of the trench can be greater without the metal plug becoming loose and separating from the underlying interconnection line.