A method for reducing capacitances between semiconductor devices is provided. A plurality of contact structures is formed in a dielectric layer. A mask is formed to cover the contact structures wherein the mask has mask features for exposing parts of the dielectric layer wherein the mask features have widths. The widths of the mask features are shrunk with a sidewall deposition. Gaps are etched into the dielectric layer through the sidewall deposition. The gaps are closed to form pockets in the gaps.