Interconnect structure with a mushroom-shaped oxide capping layer and method for fabricating same

摘要

An interconnect structure is provided that includes a dielectric material 52′ having a dielectric constant of 4.0 or less and including a plurality of conductive features 56 embedded therein. The dielectric material 52′ has an upper surface 52r that is located beneath an upper surface of each of the plurality of conductive features 56. A first dielectric cap 58 is located on the upper surface of the dielectric material 52′ and extends onto at least a portion of the upper surface of each of the plurality of conductive features 56. As shown, the first dielectric cap 58 forms an interface 59 with each of the plurality of conductive features 56 that is opposite to an electrical field that is generated by neighboring conductive features. The inventive structure also includes a second dielectric cap 60 located on an exposed portion of the upper surface of each of the plurality of conductive features 56 not covered with the first dielectric cap 58. The second dielectric cap 60 further covers on an exposed surface of the first dielectric cap 58.