Patent ID: 6995073

Claim:
A method to form an air gap interconnect structure comprising: forming a multi-layer interconnect adjacent a substrate layer, the interconnect comprising conductive layers positioned in at least two conductive vertical series, the conductive vertical series isolated from each other by sacrificial dielectric material; forming a protective layer adjacent the interconnect; patterning the protective layer to expose portions of the sacrificial dielectric material; decomposing portions of the sacrificial dielectric material to form a sacrificial dielectric decomposition product; removing portions of the sacrificial dielectric decomposition product to form air gaps between the conductive layers; and wherein forming a multi-layer interconnect comprises; forming a first layer of sacrificial dielectric material, forming trenches in the first layer, and filling the trenches with conductive material to form at least two conductive layers isolated from each other by the sacrificial dielectric material; and forming a second layer of sacrificial dielectric material adjacent the at least two conductive layers and fist layer, forming trenches in the second layer in substantial vertical alignment with the trenches of the first layer, and filling the trenches with conductive material to form at least two additional conductive layers isolated from each other by the second sacrificial dielectric material and forming vertical support structures peripheral to the conductive vertical series, wherein removing portions of the sacrificial dielectric decomposition product further forms air gaps between the vertical support structures and the conductive vertical series.