A method of treating a dielectric layer on a substrate is described. The method comprises forming the dielectric layer on the substrate, wherein the dielectric layer comprises a dielectric constant value less than the dielectric constant of SiO.sub.2. A feature pattern is formed in the dielectric layer using an etching process. Following the etching process, the feature pattern is treated using a nitrogen-containing plasma in order to form nitride surface layers by introducing nitrogen to the exposed surfaces of the dielectric layer in the feature pattern. Thereafter, the feature pattern is selectively etched to partially or fully remove the nitride surface layers.