Abstract: Capacitance between interconnects lines of a semiconductor device is reduced by providing air voids between the interconnects. The air voids are produced by depositing a dielectric over and partially between the pairs of interconnects and the substrate between them, and etching (preferably by sputter etch) in a controlled and coordinated manner so as to produce air voids in the dielectric between the interconnects. The tops of the air voids are below the level to which the uppermost surfaces of the interconnect is then exposed during subsequent processing so that the air voids remain intact during such subsequent processing.