Patent ID: 7842600
Filing Date: 2010-11-30
Classification: H01L

Abstract:
1. A method of forming an interlayer dielectric having an air gap, the method comprising: forming a first insulating layer on a semiconductor substrate, the first insulating layer defining a trench; forming a metal wire in the trench such that the metal wire is recessed beneath an upper surface of the first insulating layer; forming a metal layer on the metal wire, wherein the metal layer comprises a capping layer portion filling the recess, a upper portion formed on the capping layer portion, and an overhang portion formed on the portion of the first insulating layer adjacent to the trench protruding sidewards from the upper portion; removing the first insulating layer; forming a second insulating layer on the semiconductor substrate to cover the metal layer, whereby an air gap is formed below the overhang portion of the metal layer; removing a portion of the second insulating layer to expose the upper portion of the metal layer; removing the upper portion and the overhang portion of the metal layer; and forming a third insulating layer on the semiconductor substrate from which the upper portion and the overhang portion have been removed to maintain the air gap.