This work focuses on the fine-line patterning of benzocyclobutene (BCB), a silicon containing, thermoset polymer for potential application as an interlayer dielectric (ILD) in multilevel metallization. Etch rates for BCB have been determined in p asmas containing mixtures of O 2 and CF 4 . Conditions needed to optimize the patternability of BCB have been determined with respect to etch rates and trench sidewall profiles. A trilevel system consisting of an imaging layer, a barrier layer (hard mask), and the polymer ILD has been employed to fabricate submicron trenches and inlayed structures of the dual damascene type. Effects of plasma treatment on the surface of BCB are also reported.