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.