Abstract: A method for forming a dual damascene interconnect structure provides an intermetal dielectric that includes a spin-on low-k dielectric material formed over a CVD low-k dielectric material. A via opening is formed by etching through the spin-on low-k dielectric material and the CVD low-k dielectric material and a plug material is introduced to fill the via opening. A highly selective trench etching operation etches a trench in the upper, spin-on low-k dielectric material and removes the plug material from the via without attacking the lower CVD low-k dielectric material to form the dual damascene opening which is then filled with a conductive interconnect material. The intermetal dielectric formed of multiple low-k dielectric layers provides advantageous electrical and mechanical properties.

Abstract: A method for plasma etching is disclosed with improved etching selectivity for a nitride containing DARC and a low-k dielectric layer. Plasma chemistry is controlled by adjusting a nitrogen to oxygen ratio to achieve improved etching selectivity in both nitride containing and low-k dielectric layers. Nitrogen to oxygen ratios are adjusted to control etching of for example, a DARC nitride containing layer, and Carbon to fluorine ratios are additionally adjusted to control etching in a low-k dielectric layer.

Abstract: A new method is provided for the removal of polymer, possibly mixed with copper oxide residue, from exposed surfaces after an etch stop layer has been removed. The exposed surfaces are treated with a first plasma etch followed by a DI water rinse after which a second plasma etch of the exposed surfaces is performed. By selecting the chemistry and the conditions for the first and the second plasma etch, polymer residues and formed copper oxide residues are removed from the exposed surfaces.

Abstract: A method for plasma etching is disclosed with improved etching selectivity for a nitride containing DARC and a low-k dielectric layer. Plasma chemistry is controlled by adjusting a nitrogen to oxygen ratio to achieve improved etching selectivity in both nitride containing and low-k dielectric layers. Nitrogen to oxygen ratios are adjusted to control etching of for example, a DARC nitride containing layer, and Carbon to fluorine ratios are additionally adjusted to control etching in a low-k dielectric layer.