An integrated circuit interconnect structure. The structure includes a
substrate and a layer of transistor elements overlying the substrate. A
first interlayer dielectric layer is formed overlying the layer of
transistor elements. An etch stop layer is formed overlying the first
interlayer dielectric layer. A contact structure including metallization
is within the first interlayer dielectric layer and a metal layer is
coupled to the contact structure. A passivation layer is formed overlying
the metal layer. Preferably, an air gap layer is coupled between the
passivation layer and the metal layer, the air gap layer allowing a
portion of the metal layer to be free standing. Depending upon the
embodiment, a portion of the air gap layer may be filled with silicon
bearing nanoparticles, which may be oxidized at low temperatures. This
oxidized layer provides mechanical support and low k dielectric
characteristics. Preferably, a portion of the air gap layer is filled
with a low k dielectric material as well.