Metal fuse structure for improved programming capability
View Patent ↗Structure providing more reliable fuse blow location, and method of making the same. A vertical metal fuse blow structure has, prior to fuse blow, an intentionally damaged portion of the fuse conductor. The damaged portion helps the fuse blow in a known location, thereby decreasing the resistance variability in post-blow circuits. At the same time, prior to fuse blow, the fuse structure is able to operate normally. The damaged portion of the fuse conductor is made by forming an opening in a cap layer above a portion of the fuse conductor, and etching the fuse conductor. Preferably, the opening is aligned such that the damaged portion is on the top corner of the fuse conductor. A cavity can be formed in the insulator adjacent to the damaged fuse conductor. The damaged fuse structure having a cavity can be easily incorporated in a process of making integrated circuits having air gaps.
1. A pre-blow fuse structure comprising:
a first connection disposed within a first insulator layer;
a second connection disposed within a second insulator layer;
a conductor having a damaged portion, the conductor being disposed within a third insulator layer between the first connection within the first insulator layer and the second connection within the second insulator layer;
a dielectric cap layer between the third insulator layer and the second insulator layer; and
a cavity within the third insulator layer adjacent to the conductor,
wherein the damaged portion is disposed adjacent to a first opening within the dielectric cap layer, and
wherein the second insulator layer is directly over the cavity.
2. The structure of claim 1 , wherein the pre-blow fuse structure is a stacked via structure.
3. The structure of claim 1 , wherein the conductor is a line level conductor.
4. The structure of claim 1 , wherein the damaged portion is proximate a top corner of the conductor.
5. The structure of claim 1 , wherein the damaged portion is proximate a sidewall of the conductor.
6. The structure of claim 1 , wherein the damaged portion of the conductor includes a bulk conductor, a liner, or a combination of both.
7. The structure of claim 1 , wherein the damaged portion includes a missing portion of the conductor, a corroded portion of the conductor, an oxidized portion of the conductor, or a combination of two or more of the previously described damage.
8. The structure of claim 1 , wherein the damaged portion is proximate the cavity, the cavity being disposed within the third insulator layer and the third insulator being a fuse level dielectric.
9. The structure of claim 1 , wherein a portion of the second insulator layer is above at least a portion of the damaged portion.
10. The structure of claim 1 , wherein the damaged portion is in contact with a dielectric layer.
11. The structure of claim 8 , further comprising a non-fuse bank area, wherein the non-fuse bank area has a second cavity between a pair of interconnects.
12. The structure of claim 11 , further comprising a second opening in the dielectric cap layer, wherein the second opening is aligned equidistant between the pair of interconnects.
13. The structure of claim 1 , wherein the damaged portion is disposed between a portion of the conductor and the second insulator layer.
14. The structure of claim 1 , wherein the first insulator layer, the second insulator layer, and the third insulator layer are distinct from one another.
15. The structure of claim 9 , wherein the portion of the second insulator layer is directly above at least the portion of the damaged portion.