Sacrificial metal spacer dual damascene

Abstract

A method and structure for a dual damascene interconnect structure comprises forming wiring lines in a metallization layer over a substrate, shaping a laminated insulator stack above the metallization layer, patterning a hardmask over the laminated insulator stack, forming troughs in the hardmask, creating sacrificial tungsten sidewall spacers in the troughs, patterning the laminated insulator stack, removing the sacrificial sidewall spacers, forming vias in the patterned laminated insulator stack, and depositing a metal liner and conductive material into the vias and troughs, wherein the laminated insulator stack comprises a dielectric layer further comprising oxide and polyarylene. The step of depositing prevents the laminated insulator stack from sputtering into the vias. Moreover, the step of depositing comprises cleaning the vias and troughs, optionally performing a reactive ion etching or argon sputter cleaning, depositing a plurality of metal layers over the vias and troughs, and depositing copper in the vias and troughs.

1 . An integrated circuit structure comprising:
 a wiring layer having wires;   a first insulator layer on said wiring layer, said first insulator layer having a first dielectric constant;   a second insulator layer on said first insulator layer, said second insulator layer having a second dielectric constant lower than said first dielectric constant;   openings through said first insulator layer and said second insulator layer to said wires;   a metal liner lining sides of said openings; and   conductor filling said openings.   
     
     
         2 . The structure in  claim 1 , further comprising a second metal liner between said metal liner and said conductor. 
     
     
         3 . The structure in  claim 2 , wherein said second metal liner is further positioned along a bottom of said openings between said conductor and said wires, such that said second metal liner separates said conductor form said wires. 
     
     
         4 . The structure in  claim 1 , wherein said metal liner is positioned only along sides of said openings. 
     
     
         5 . The structure in  claim 1 , wherein said metal liner protects said second insulator layer during formation of said structure. 
     
     
         6 . An integrated circuit structure comprising:
 a wiring layer having wires;   a first insulator layer on said wiring layer, said first insulator layer having a first dielectric constant;   a second insulator layer on said first insulator layer, said second insulator layer having a second dielectric constant lower than said first dielectric constant;   openings through said first insulator layer and said second insulator layer to said wires;   a metal liner lining sides of said openings;   conductor filling said openings; and   a second metal liner between said metal liner and said conductor.   
     
     
         7 . The structure in  claim 6 , wherein said second metal liner is further positioned along a bottom of said openings between said conductor and said wires, such that said second metal liner separates said conductor form said wires. 
     
     
         8 . The structure in  claim 6 , wherein said metal liner is positioned only along sides of said openings. 
     
     
         9 . The structure in  claim 6 , wherein said metal liner protects said second insulator layer during formation of said structure. 
     
     
         10 . An integrated circuit structure comprising:
 a wiring layer having wires;   a first insulator layer on said wiring layer, said first insulator layer having a first dielectric constant;   a second insulator layer on said first insulator layer, said second insulator layer having a second dielectric constant lower than said first dielectric constant;   openings through said first insulator layer and said second insulator layer to said wires;   a metal liner lining sides of said openings;   conductor filling said openings; and   a second metal liner between said metal liner and said conductor,   wherein said second metal liner is further positioned along a bottom of said openings between said conductor and said wires, such that said second metal liner separates said conductor form said wires.   
     
     
         11 . The structure in  claim 10 , wherein said metal liner is positioned only along sides of said openings. 
     
     
         12 . The structure in  claim 10 , wherein said metal liner protects said second insulator layer during formation of said structure.