Method of dual damascene patterning

The invention relates to the field of fabricating integrated circuits and other electronic devices and in particular to an improved method of photoresist patterning that provides a wider process latitude and higher yield during the formation of dual damascene structures. An improved method of patterning photoresist during formation of damascene structures is provided which involves a process that is resistant to poisoning from adjacent layers. An inert resin is used to fill vias in a damascene stack. Then a second stack comprised of an underlayer, a non-photosensitive Si-containing layer, an ARC, and a photoresist are formed on the first stack. A trench pattern formed in the photoresist is etch transferred into the first stack. The Si-containing layer that is preferably a spin-on material can be optimized for thermal and etch resistance without compromising lithographic properties since it is not photosensitive. The state of the art photoresist provides a large process window for printing small features with no scum. The inert resin, underlayer, and silicon containing layers are independent of exposure wavelength and can be readily implemented into existing or future manufacturing schemes.