A method of forming a semiconductor device includes: forming a lower trace in a lower dielectric layer; reducing a height of the lower trace a distance equal to gap height (g) to form an initial void region; filling the initial void region with an amorphous carbon layer; forming an upper dielectric layer above the amorphous carbon layer; covering the amorphous carbon layer with at least an oxide layer and a nitride layer; forming a hole in the oxide and nitride layers to expose a portion of the amorphous carbon layer; exposing the amorphous carbon layer to oxygen plasma to remove the amorphous carbon layer; sputtering a metal layer over the oxide layer and into a void created removal of the amorphous carbon layer to divide the void such that it includes an airgap; and forming an upper trace over the airgap.