The present disclosure involves forming a porous low-k dielectric structure. A plurality of conductive elements is formed over the substrate. The conductive elements are separated from one another by a plurality of openings. A barrier layer is formed over the conductive elements. The barrier layer is formed to cover sidewalls of the openings. A treatment process is performed to the barrier layer. The barrier layer becomes hydrophilic after the treatment process is performed. A dielectric material is formed over the barrier layer after the treatment process has been performed. The dielectric material fills the openings and contains a plurality of porogens.