Some embodiments relate to a method for forming an integrated chip, the method includes forming a first conductive wire and a second conductive wire over a substrate. A dielectric structure is formed laterally between the first conductive wire and the second conductive wire. The dielectric structure comprises a first dielectric liner, a dielectric layer disposed between opposing sidewalls of the first dielectric liner, and a void between an upper surface of the first dielectric liner and a lower surface of the dielectric layer. A dielectric capping layer is formed along an upper surface of the dielectric structure. Sidewalls of the dielectric capping layer are aligned with sidewalls of the dielectric structure.