Methods are provided for forming a structure that includes an air gap. In one embodiment, a method is provided for forming a damascene structure including depositing a porous low dielectric constant layer by a method including reacting an organosilicon compound and a porogen-providing precursor, depositing a porogen-containing material, and removing at least a portion of the porogen-containing material, depositing an organic layer on the porous low dielectric constant layer by reacting the porogen-providing precursor, forming a feature definition in the organic layer and the porous low dielectric constant layer, filing the feature definition with a conductive material therein, depositing a mask layer on the organic layer and the conductive material disposed in the feature definition, forming apertures in the mask layer to expose the organic layer, removing a portion or all of the organic layer through the apertures, and forming an air gap adjacent the conductive material.