Interconnect structure and method of making same

Abstract

An interconnect structure and method of fabricating the same is provided. More specifically, the interconnect structure is a defect free capped interconnect structure. The structure includes a conductive material formed in a trench of a planarized dielectric layer which is devoid of cap material. The structure further includes the cap material formed on the conductive material to prevent migration. The method of forming a structure includes selectively depositing a sacrificial material over a dielectric material and providing a metal capping layer over a conductive layer within a trench of the dielectric material. The method further includes removing the sacrificial material with any unwanted deposited or nucleated metal capping layer thereon.

What is claimed is: 
     
         1 . A structure, comprising:
 a conductive layer formed in a trench of a planarized dielectric layer, a top surface of the conductive layer being at a coplanar level as a top surface of the dielectric layer;   a liner completely lining sidewalls and a bottom of the trench;   a sacrificial layer formed selective to an exposed surface of the planarized dielectric layer;   a cap layer formed on the conductive layer to prevent migration, the planarized dielectric layer being devoid of the cap layer, and the cap layer being in physical contact with the conductive layer; and   unwanted deposition and/or rogue nucleation material formed on the sacrificial layer, wherein the unwanted deposition and/or rogue nucleation is a same material as the cap layer.   
     
     
         2 . The structure of  claim 1 , wherein the cap layer is one of CoWB and CoWP of different compositions. 
     
     
         3 . The structure of  claim 1 , wherein the liner extends below portions of the conductive layer within the trench. 
     
     
         4 . The structure of  claim 3 , wherein the liner is tantalum, tantalum nitride, titanium, titanium nitride or Ruthenium. 
     
     
         5 . The structure of  claim 1 , wherein the planarized dielectric layer is silicon oxide, carbon doped oxide, SiCxOyHz or a porous dielectric material. 
     
     
         6 . The structure of  claim 1 , wherein the sacrificial layer has a ratio of deposition rate on the planarized dielectric layer to a deposition rate on copper of about 2 or greater. 
     
     
         7 . The structure of  claim 1 , wherein the sacrificial layer is one of hydrophobic, a variety of silylating agents, and a variety of polyxylylene polymers. 
     
     
         8 . The structure of  claim 1 , wherein the sacrificial layer prevents the unwanted deposition and/or rogue nucleation of the cap layer on the planarized dielectric layer. 
     
     
         9 . The structure of  claim 1 , further comprising:
 a lower dielectric layer having a lower trench;   a lower cap layer formed on the lower dielectric layer, the planarized dielectric layer formed on the lower cap layer;   a planarized dielectric layer, formed on the lower cap layer, having an upper trench; and   a via aligned with the lower trench and structured to connect the trench with the lower trench, the via being formed through the planarized dielectric layer and the lower cap layer into the lower conductive layer,   wherein the liner extends through the lower cap layer, and a bottom surface of a bottom portion of the liner is non-planar and below a top surface of the lower dielectric layer.   
     
     
         10 . An intermediate structure, comprising:
 a first dielectric layer having a first trench filled with a first conductive layer;   a second dielectric layer formed over the first dielectric layer, the second dielectric layer having a via and a second trench, wherein the via and the second trench are lined with a liner and filled with a second conductive layer on the liner, a top surface of the second conductive layer being at a coplanar level as a top surface of the second dielectric layer, the second dielectric layer being devoid of unwanted deposition or nucleation of a capping layer, and the capping layer being on the second conductive layer;   a sacrificial layer placed on an entire exposed surface of the second dielectric layer, which prevents the capping layer from depositing on the second dielectric layer, the capping layer being devoid of the sacrificial layer; and   a plurality of isolated deposits of a nucleated cap material formed on the sacrificial material,   wherein the nucleated cap material comprises a same material as the capping layer.   
     
     
         11 . The intermediate structure of  claim 10 , wherein the liner is tantalum, tantalum nitride, titanium, titanium nitride or Ruthenium. 
     
     
         12 . The intermediate structure of  claim 10 , wherein the first conductive layer and the second conductive material are copper. 
     
     
         13 . The intermediate structure of  claim 10 , wherein the sacrificial layer has a ratio of deposition rate on the second dielectric layer to a deposition rate on the second conductive layer of about 2 or greater. 
     
     
         14 . The intermediate structure of  claim 10 , wherein the sacrificial layer is at least one of:
 hydrophobic and has silylating agents, and a variety of polyxylylene polymers.   
     
     
         15 . The intermediate structure of  claim 10 , wherein the sacrificial layer prevents unwanted deposition and/or rogue nucleation of the capping layer on the second dielectric layer. 
     
     
         16 . The intermediate structure of  claim 10 , wherein:
 the capping layer is one of CoWB and CoWP of different compositions; and   the capping layer is in physical contact with the second conductive layer.   
     
     
         17 . The intermediate structure of  claim 10 , further comprising a lower capping layer formed on the first dielectric layer, wherein:
 the second dielectric layer is formed on the lower capping layer;   the via aligns with the first trench and connects with the second trench, extends from the second dielectric layer through the lower capping layer and into the first trench;   the liner extends below portions of the second conductive layer within the via and the second trench, extends through the lower capping layer, and extends into and in physical contact with the first conductive layer; and   the second conductive layer extends through the lower capping layer and into the first trench.