Patent ID: 7759251

Claim:
A method of fabricating a dual damascene integrated structure, comprising the steps of: forming a porous ultra-low k dielectric film on an underlying etch stop film; forming a hard-mask layer on the porous ultra-low k dielectric film; applying a first masking material layer on the hard-mask layer; forming a via pattern in the first masking material layer; transferring the via pattern in the first masking material layer through the hard-mask layer and through the porous ultra-low k dielectric film to the etch stop film so as to form therein one or more vias with exposed sidewalls; forming a first densified layer on the exposed sidewalls of the one or more vias in the porous ultra-low k dielectric film by gas cluster ion beam irradiation; removing remnants of the first masking material layer; applying a second masking material layer so as to form a layer on the hard-mask layer and to fill the one or more formed vias; forming a trench pattern in the second masking material layer; transferring the trench pattern in the second masking material layer through the hard-mask layer and at least partially through the porous ultra-low k dielectric film so as to form therein one or more trenches with exposed surfaces and sidewalls; removing remnants of the second masking material layer; forming a second densified layer on the exposed surfaces and sidewalls of the one or more trenches; and etching the structure by gas cluster ion beam irradiation to open the underlying etch stop layer in the one or more vias and to either partially or completely remove the hard-mask layer.