Methods for fabricating integrated circuits are provided. In one example, a method for fabricating an integrated circuit includes forming a sidewall in a porous low-k dielectric layer that overlies a semiconductor substrate using a plurality of discontinuous etching treatments. Exposed portions of the sidewall are progressively sealed interposingly between the discontinuous etching treatments to form a sealed sidewall. The sealed sidewall defines a trench in the porous low-k dielectric layer.