Direct patterning of photosensitive low-dielectric-constant films using electron-beam lithography

A direct patterning technique of interlayer dielectric films was developed for multilevel interconnections. A photosensitive methylsilazane film with a dielectric constant of 2.7 was synthesized. A methylsilazane precursor co nsists of a photoacid generator, a sensitizer, and a base polymer. The phot osensitive methylsilazane film could be patterned by use of electron-beam l ithography or ultraviolet lithography. It was demonstrated that the smalles t feature size of 50 nm for damascene lines and via holes could be directly patterned in these films by electron-beam lithography. (C) 2001 American I nstitute of Physics.