BEOL vertical fuse formed over air gap
A method of forming an electrical device that includes forming a first level including an array of metal lines, wherein an air gap is positioned between the adjacent metal lines. A second level is formed including at least one dielectric layer atop the first level. A plurality of trench structures is formed in the at least on dielectric layer. At least one of the plurality of trench structures opens the air gap. A conductive material is formed within the trenches. The conductive material deposited in the open air gap provides a vertical fuse.
1. An electrical device comprising:
a first level comprised of an array of metal lines, wherein a plurality of air gaps are present separating adjacent metal layers in the array of metal lines and one of the air gaps includes a fuse structure present therein; and
a second level including a plurality of trenches in an interlevel dielectric layer that contain electrically conductive material, wherein a first set of the plurality of trenches including said electrically conductive material extends into at least one of the air gaps to provide a vertical fuse, and a second set of trenches containing the electrically conductive material does not extend to the first level and provides interconnect structures.
2. The electrical device of claim 1 , wherein the first set of the plurality of trenches includes a line portion having a first depth and a via portion having a second depth, the second depth being greater than the first depth and extending to the air gaps.
3. The electrical device of claim 2 , wherein the via portions provide a first contact region and a second contract region to the vertical fuse, and the electrically conductive material in the air gaps provides a fuse link.
4. The electrical device of claim 3 , wherein at least one interface between the via portions that provide the first contact region and the second contact region and the electrically conductive material in the air gap that provides the fuse link has a necked opening with a width that is less than half the dimension separating adjacent metal lines in the array of metal lines.
5. The electrical device of claim 4 , wherein said with of the necked region ranges from 5 nm to 40 nm.
6. The electrical device of claim 3 , wherein the fuse link is entirely present in the first level.
7. The electrical device of claim 1 , wherein the vertical fuse is blown by currents ranging from 10 mA to 15 mA.