Spin-on cap layer, and semiconductor device containing same

A Cu interconnect structure comprising:

• a substrate having a patterned low-k interlevel dielectric located thereon, said patterned low-k interlevel dielectric having an effective dielectric constant of about 3.5 or less;
• a Cu conductive region formed within said patterned low-k interlevel dielectric;
• a polish stop layer on surfaces of said patterned low-k interlevel dielectric not containing said Cu conductive region;
• and a spin-on cap located atop only horizontal surfaces of said Cu conductive region and said polish stop layer, wherein said spin-on cap comprises (i) a low-k dielectric having a dielectric constant of about 3.5 or less selected from the group consisting of a benzocyclobutene, aromatic thermosetting polymeric resins, silsesquioxanes, methylsilsesquioxane, hydrido-silsesquioxane, a methylsilsesquioxane-hydrido silsesquioxane copolymer, tetraethylorthosilicate, and organosilanes;
• and (ii) at least one additive selected from the soup consisting of cyanide compounds, multidentate ligands including multidentate amines, phthalocyanine, bipyridine, and etahylenediamine tetraacetate (EDTA), wherein said at least one additive is capable of binding Cu ions, and is soluble in the spin-on low-k dielectric cap.