Redundant via structure for metal fuse applications

Abstract

A metal fuse structure using redundant vias. The redundant vias are formed on one metal level in a stacked via metal fuse structure to force failures to occur in the metal level that does not have the redundant vias. The metal fuse structure includes: a first dielectric layer having a metal feature; a second dielectric layer having a first metal connector embedded therein; and a third dielectric layer having a second metal connector embedded therein. The metal connectors include at least one via and one line, and at least one metal connector has at least two vias.

What is claimed is: 
     
         1 . A metal fuse structure comprising:
 a first dielectric layer having a metal feature embedded therein, the metal feature having an upper surface;   a second dielectric layer on the first dielectric layer having a first metal connector embedded therein, having a first via and a second via and a first line above the first and second via; and   a third dielectric layer on the second dielectric layer having a second metal connector embedded therein having a third via and a second line above the third via, wherein the third via is in electrical contact with the first line.   
     
     
         2 . The metal fuse structure of  claim 1 , further comprising:
 a first cap layer on at least a portion of the first dielectric layer and the upper surface of the metal feature;   a second cap layer on at least a portion of the second dielectric layer and an upper surface of the first line; and   a third cap layer on at least a portion of the third dielectric layer and an upper surface of the second line.   
     
     
         3 . The metal fuse structure of  claim 1 , wherein the first, second and third dielectric layers are comprised of at least one of silicon oxide (SiO), silicon nitride (Si 3 N 4 ), hydrogenated silicon oxycarbide (SiCOH), silsesquioxanes, carbon-doped oxides, thermosetting polyarylene ethers, polyarylene ether, spin-on silicon-carbon contained polymer material, other low dielectric constant (<3.9) materials or layers thereof. 
     
     
         4 . The metal fuse structure of  claim 1 , wherein the metal feature, first via, second via, third via, first line and second line are comprised of at least one of copper (Cu), aluminum (Al), silver (Ag), gold (Au) or alloys thereof. 
     
     
         5 . The metal fuse structure of  claim 2 , wherein the first, second and third cap layers are comprised of at least one of silicon carbide (SiC), silicon nitride (Si 3 N 4 ), silicon dioxide (SiO 2 ), nitrogen, hydrogen doped silicon carbide (SiC(N,H)) or combinations thereof. 
     
     
         6 . The metal fuse structure of  claim 1 , further comprising:
 a liner material deposited at least along sidewalls of the first, second and third vias, and the first and second lines.   
     
     
         7 . The metal fuse structure of  claim 6 , wherein the liner material comprises at least one of tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), ruthenium (Ru), ruthenium nitride (RuN) or combinations thereof. 
     
     
         8 . A metal fuse structure comprising:
 a first dielectric layer having a metal feature embedded therein, the metal feature having an upper surface;   a second dielectric layer on the first dielectric layer having a first metal connector embedded therein, having at least a first via and a first line above the first via;   a third dielectric layer on the second dielectric layer having a second metal connector embedded therein having a second via and a second line above the second via, wherein the second via is in electrical contact with the first line; and   a third via formed in at least one of the first metal connector and the second metal connector.   
     
     
         9 . The metal fuse structure of  claim 8  further comprising:
 a first cap layer on at least a portion of the first dielectric layer and the upper surface of the metal feature; 
 a second cap layer on at least a portion of the second dielectric layer and an upper surface of the first line; and 
 a third cap layer on at least a portion of the third dielectric layer and an upper surface of the second line. 
 
     
     
         10 . The metal fuse structure of  claim 8  further comprising:
 a liner material deposited at least along sidewalls of the first, second and third vias, and the first and second lines. 
 
     
     
         11 . The metal fuse structure of  claim 8 , wherein the first, second and third dielectric layers are comprised of at least one of silicon oxide (SiO), silicon nitride (Si 3 N 4 ), hydrogenated silicon oxycarbide (SiCOH), silsesquioxanes, carbon-doped oxides, thermosetting polyarylene ethers, polyarylene ether, spin-on silicon-carbon contained polymer material, other low dielectric constant (<3.9) materials or layers thereof. 
     
     
         12 . The metal fuse structure of  claim 8 , wherein the metal feature, first via, second via, third via, first line and second line are comprised of at least one of copper (Cu), aluminum (Al), silver (Ag), gold (Au) or alloys thereof. 
     
     
         13 . The metal fuse structure of  claim 9 , wherein the first, second and third cap layers are comprised of at least one of silicon carbide (SiC), silicon nitride (Si 3 N 4 ), silicon dioxide (SiO 2 ), nitrogen, hydrogen doped silicon carbide (SiC(N,H)) or combinations thereof. 
     
     
         14 . The metal fuse structure of  claim 10 , wherein the liner material comprises at least one of tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), ruthenium (Ru), ruthenium nitride (RuN) or combinations thereof.