Semiconductor device and fabrication method thereof

Abstract

A semiconductor device including a substrate, a spacer and a high-k dielectric layer having a U-shape profile is provided. The spacer located on the substrate surrounds and defines a trench. The high-k dielectric layer having a U-shape profile is located in the trench, and the high-k dielectric layer having a U-shape profile exposes an upper portion of the sidewalls of the trench.

1 . A semiconductor device, comprising:
 a substrate;   an inter layer dielectric layer located on the substrate;   a trench located in the inter layer dielectric layer; and   a high-k dielectric layer having a U-shape profile located within the trench, wherein the high-k dielectric layer exposes an upper portion of the sidewalls of the trench.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the high-k dielectric layer having a U-shape profile comprises a metal containing dielectric layer. 
     
     
         3 . The semiconductor device according to  claim 2 , wherein the high-k dielectric layer having a U-shape profile comprises a metal layer located on the two ends of the U-shaped cross-sectional profile of the high-k dielectric layer having a U-shape profile. 
     
     
         4 . The semiconductor device according to  claim 3 , wherein the metal containing dielectric layer is a chemical compound of the metal layer. 
     
     
         5 . The semiconductor device according to  claim 1 , further comprising a work function metal layer located on the high-k dielectric layer having a U-shape profile. 
     
     
         6 . The semiconductor device according to  claim 5 , wherein the two ends of the work function metal layer are trimmed with the two ends of the high-k dielectric layer having a U-shape profile. 
     
     
         7 . A fabricating method of a semiconductor device, comprising:
 forming a inter layer dielectric layer on a substrate;   forming a trench in the inter layer dielectric layer;   forming a high-k dielectric layer having a U-shape profile in the trench; and   recessing the high-k dielectric layer to expose an upper portion of the sidewalls of the trench.   
     
     
         8 . The fabricating method of the semiconductor device according to  claim 7 , wherein recessing the high-k dielectric layer, further comprising:
 filling a filling material in the trench; and   etching back the filling material to expose the two ends of the U-shape profile of the high-k dielectric layer.   
     
     
         9 . The fabricating method of the semiconductor device according to  claim 8 , after etching back the filling material, further comprising:
 transferring the two ends of the U-shape profile to transform it to a metal layer, wherein the transferring step is a reduction.   
     
     
         10 . The fabricating method of the semiconductor device according to  claim 9 , after transferring the two ends of the U-shape profile to transform it to the metal layer, further comprising:
 removing at least a portion of the metal layer.   
     
     
         11 . The fabricating method of the semiconductor device according to  claim 7 , after forming a high-k dielectric layer having a U-shape profile in the trench, further comprising:
 forming a barrier layer on the high-k dielectric layer.   
     
     
         12 . The fabricating method of the semiconductor device according to  claim 8 , wherein the filling material comprises a photoresist material, a bottom anti-reflection coating (BARC) or a light absorbing Si-content polymer (DUO). 
     
     
         13 . The fabricating method of the semiconductor device according to  claim 9 ,
 after transferring the two ends of the U-shape profile to transform it to the metal layer, further comprising:   removing a portion of the metal layer; and   removing the filling material.   
     
     
         14 . The fabricating method of the semiconductor device according to  claim 13 , after removing the filling material, further comprising:
 forming a work function metal layer on the high-k dielectric layer having a U-shape profile.   
     
     
         15 . The fabricating method of the semiconductor device according to  claim 13 , after transferring the two ends of the U-shape profile to transform it to the metal layer, further comprising:
 forming a work function metal layer on the high-k dielectric layer having a U-shape profile; and   removing a portion of the work function metal layer to expose the metal layer.   
     
     
         16 . The fabricating method of the semiconductor device according to  claim 15 , wherein removing a portion of the work function metal layer to expose the metal layer and removing the metal layer are finished in the same removing process. 
     
     
         17 . A fabricating method of the semiconductor device, comprising:
 forming a inter layer dielectric layer on a substrate;   forming a trench in the inter layer dielectric layer;   forming a high-k dielectric layer having a U-shape profile in the trench;   
       forming a work function metal layer having a U-shape profile on the high-k dielectric layer having a U-shape profile;
 filling a filling material into the trench; 
 etching back the filling material to expose the two ends of the work function metal layer and the two ends of the high-k dielectric layer; 
 reducing the two ends of the high-k dielectric layer to transform it to a metal layer; 
 removing the two ends of the work function metal layer and the metal layer; and 
 removing the filling material. 
 
     
     
         18 . The fabricating method of the semiconductor device according to  claim 17 , wherein the work function metal layer having a U-shaped cross-sectional profile comprises a titanium nitride metal layer. 
     
     
         19 . The fabricating method of the semiconductor device according to  claim 17 , wherein the work function metal layer having a U-shaped cross-sectional profile comprises an titanium aluminum (TiAl) metal layer and a titanium nitride metal layer. 
     
     
         20 . The fabricating method of the semiconductor device according to  claim 17 , after removing the filling material, further comprising:
 forming a filling metal layer on the work function metal layer having a U-shaped cross-sectional profile.