Electronic fuse vias in interconnect structures
View Patent ↗An electronic fuse and method for forming the same. Embodiments of the invention include e-fuses having a first metallization level including a metal structure, a second metallization level above the first metallization level, a metal via in the second metallization level, an interface region where the metal via meets the first metallization level, and a damaged region at the interface region. Embodiments further include a method including providing a first metallization level including a metal structure, forming a capping layer on the first metallization level, forming an opening in the capping layer that exposes a portion of the metal structure; forming above the capping layer an adhesion layer contacting the metal structure, forming an insulating layer above the adhesion layer, etching the insulating layer and the adhesion layer to form a recess exposing the metal structure, and filling the fuse via recess to form a fuse via.
1. A method of forming a vertical electronic fuse structure, the method comprising:
providing a first metallization level including a first metal structure having a top surface substantially flush with a top surface of the first metallization level;
forming a capping layer on the top surface of the first metallization level;
forming an opening in the capping layer that exposes a portion of the top surface of the first metal structure;
forming an adhesion layer above the capping layer, wherein the adhesion layer lines the opening in the capping layer and contacts the first metal structure;
forming an insulating layer above the adhesion layer;
etching the insulating layer and the adhesion layer to form a fuse via recess, wherein the fuse via recess exposes the top surface of the first metal structure; and
filling the fuse via recess to form a fuse via.
2. The method of claim 1 , further comprising forming a weakened region at the top surface of the first metal structure.
3. The method of claim 2 , wherein forming the weakened region comprises subjecting the exposed portion of the top surface of the first metal structure to a plasma ashing process.
4. The method of claim 1 , wherein forming the adhesion layer comprises depositing a SiO2 layer on the capping layer and on the exposed portion of the top surface of the first metal structure, and wherein depositing the SiO2 layer causes oxygen from the SiO2 layer to migrate into the first metal structure to form a weakened region at the top surface of the first metal structure.
5. The method of claim 1 , wherein etching the insulating and adhesion layers forms a damaged region at a bottom of the fuse via recess.
6. The method of claim 5 , wherein the damaged region comprises a void.
7. The method of claim 6 , wherein the damaged region comprises a flared bottom, and wherein the bottom of the fuse via recess is wider than a middle of the fuse via recess.
8. The method of claim 1 , wherein etching the insulating and adhesion layers includes a dilute hydrofluoric acid wet clean.
9. The method of claim 1 , further comprising:
providing a second metal structure having a top surface substantially flush with the top surface of the first metallization level;
etching the insulating layer, adhesion layer, and capping layer to form a non-fuse via recess, wherein the non-fuse via recess exposes the top surface of the second metal structure; and
filling the non-fuse via recess to form a non-fuse via.