Self-assembled mono-layer liner for cu/porous low-k interconnections

Abstract

An interconnect structure of an integrated circuit includes a low-k dielectric layer over a semiconductor substrate, a conductor in the low-k dielectric layer, and a dielectric transition layer between the low-k dielectric layer and the conductor, wherein the dielectric transition layer has a thickness of less than about 50 Å.

1 . An integrated circuit comprising:
 a low-k dielectric layer over a semiconductor substrate;   a conductor in the low-k dielectric layer; and   a dielectric transition layer between the low-k dielectric layer and the conductor, wherein the dielectric transition layer has a thickness of less than about 50 Å.   
   
   
       2 . The integrated circuit of  claim 1  further comprising a diffusion barrier layer on the dielectric transition layer, wherein an atomic percentage of atoms of the diffusion barrier layer in the dielectric transition layer is less than about 0.1%. 
   
   
       3 . The integrated circuit of  claim 2 , wherein the diffusion barrier layer comprises a material selected from the group consisting essentially of titanium, titanium nitride, tantalum, tantalum nitride, and combinations thereof. 
   
   
       4 . The integrated circuit of  claim 2 , wherein a bottom portion of the diffusion barrier layer is located on a metallic feature, and wherein the metallic feature is in an additional dielectric layer underlying the low-k dielectric layer, and wherein substantially no dielectric transition layer exists on the metallic feature. 
   
   
       5 . The integrated circuit of  claim 1 , wherein the dielectric transition layer has a thickness of between about 10 Åand about 30 Å. 
   
   
       6 . The integrated circuit of  claim 1 , wherein the dielectric transition layer comprises terminals selected from the group consisting essentially of methyl, ethyl, propyl, and combinations thereof. 
   
   
       7 . The integrated circuit of  claim 1 , wherein the dielectric transition layer has a higher carbon concentration than the low-k dielectric layer has. 
   
   
       8 . The integrated circuit of  claim 1 , wherein the low-k dielectric layer has a dielectric constant of less than about 2.5. 
   
   
       9 . An integrated circuit comprising:
 a porous dielectric layer over a semiconductor substrate;   a conductor in the porous dielectric layer; and   a mono-layer between and adjoining the porous dielectric layer and the conductor, wherein the mono-layer comprises terminals selected from the group consisting essentially of methyl, ethyl, propyl, and combinations thereof.   
   
   
       10 . The integrated circuit of  claim 9 , wherein the terminals comprise methyl. 
   
   
       11 . The integrated circuit of  claim 9 , wherein the mono-layer has a carbon concentration higher than a carbon concentration in the low-k dielectric layer. 
   
   
       12 . The integrated circuit of  claim 11 , wherein the carbon concentration in the mono-layer is higher than a carbon concentration in the low-k dielectric layer by about three to about 15 percent. 
   
   
       13 . The integrated circuit of  claim 9 , wherein the mono-layer exists only at surfaces of the low-k dielectric layer. 
   
   
       14 . The integrated circuit of  claim 9 , wherein the mono-layer comprises Si—(CH 3 ) 3  terminals. 
   
   
       15 . An integrated circuit comprising:
 a porous dielectric layer over a semiconductor substrate;   an opening in the porous dielectric layer;   a dielectric transition layer on at least sidewalls of the porous dielectric layer in the opening, wherein the dielectric transition layer has a thickness of less than about 50 Å, and wherein a first carbon concentration in the dielectric transition layer is greater than a second carbon concentration in the porous dielectric layer; and   a diffusion barrier layer on the dielectric transition layer.   
   
   
       16 . The integrated circuit of  claim 15 , wherein the first carbon concentration is greater than the second carbon concentration by about three to about 15 percent.