Fin field effect transistor device structure

Abstract

A fin field effect transistor device structure includes a fin structure formed over a substrate. The fin field effect transistor device structure also includes a source/drain epitaxial structure formed over the fin structure. The fin field effect transistor device structure also includes a contact structure with a concave top surface formed over the source/drain epitaxial structure. The fin field effect transistor device structure also includes a barrier layer conformally wrapped around the contact structure. The fin field effect transistor device structure also includes a via structure formed over the contact structure. The concave top surface of the contact structure is below the top surface of the barrier layer.

What is claimed is: 
     
         1 . A fin field effect transistor device structure, comprising:
 a fin structure formed over a substrate;   a source/drain epitaxial structure formed over the fin structure;   a contact structure with a concave top surface formed over the source/drain epitaxial structure;   a barrier layer conformally wrapped around the contact structure; and   a via structure formed over the contact structure, wherein the concave top surface of the contact structure is below a top surface of the barrier layer.   
     
     
         2 . The fin field effect transistor device structure as claimed in  claim 1 , wherein the via structure comprises a single layer of conductive material. 
     
     
         3 . The fin field effect transistor device structure as claimed in  claim 1 , wherein the contact structure comprises tungsten and the via structure comprises ruthenium. 
     
     
         4 . The fin field effect transistor device structure as claimed in  claim 1 , further comprising:
 a tip portion of the via structure protruding through the concave top surface of the contact structure.   
     
     
         5 . The fin field effect transistor device structure as claimed in  claim 4 , wherein the tip portion of the via structure has a needle shape, a V-shape, or a U-shape. 
     
     
         6 . The fin field effect transistor device structure as claimed in  claim 4 , wherein the contact structure below the tip portion of the via structure is separated. 
     
     
         7 . A fin field effect transistor device structure, comprising:
 a fin structure over a substrate;   a source/drain epitaxial structure over the fin structure;   a contact structure with a seam over the source/drain epitaxial structure; and   a via structure over the contact structure, wherein the via structure has a tip portion, and the tip portion of the via structure is separated from the contact structure by the seam.   
     
     
         8 . The fin field effect transistor device structure as claimed in  claim 7 , wherein the contact structure has a concave top surface. 
     
     
         9 . The fin field effect transistor device structure as claimed in  claim 7 , further comprising:
 a metal semiconductor compound layer between the contact structure and the source/drain epitaxial structure.   
     
     
         10 . The fin field effect transistor device structure as claimed in  claim 9 , further comprising:
 a barrier layer wrapping the contact structure and a first portion of the via structure on the metal semiconductor compound layer.   
     
     
         11 . The fin field effect transistor device structure as claimed in  claim 7 , wherein the contact structure and the via structure are made of different materials. 
     
     
         12 . The fin field effect transistor device structure as claimed in  claim 7 , further comprising:
 a first dielectric layer surrounding the source/drain epitaxial structure, the contact structure and the a first portion of the via structure.   
     
     
         13 . The fin field effect transistor device structure as claimed in  claim 12 , a second dielectric layer over the first dielectric layer, wherein the second dielectric layer surrounds a second portion of the via structure. 
     
     
         14 . The fin field effect transistor device structure as claimed in  claim 13 , wherein the via structure has a first width in the first dielectric layer and a second width in the second dielectric layer, and the first width is greater than the second width. 
     
     
         15 . A fin field effect transistor device structure, comprising:
 a fin structure over a substrate;   a source/drain epitaxial structure over the fin structure;   a contact structure over the source/drain epitaxial structure; and   a via structure over the contact structure, wherein the via structure comprises a top portion, a bottom portion below the top portion, and a tip portion below the bottom portion;   a first dielectric layer surrounding the contact structure and the bottom portion and the tip portion of the via structure; and   a second dielectric layer surrounding the top portion of the via structure over the first dielectric layer, wherein the bottom portion of the via structure has a straight sidewall in direct contact with a bottom surface of the second dielectric layer.   
     
     
         16 . The fin field effect transistor device structure as claimed in  claim 15 , wherein the tip portion of the via structure has a flat bottom surface. 
     
     
         17 . The fin field effect transistor device structure as claimed in  claim 15 , wherein a top surface of the contact structure is V-shape. 
     
     
         18 . The fin field effect transistor device structure as claimed in  claim 15 , further comprising:
 a barrier layer between the bottom portion of the via structure and the first dielectric layer and between the contact structure and the first dielectric layer.   
     
     
         19 . The fin field effect transistor device structure as claimed in  claim 15 , wherein a top surface of the bottom portion of the via structure is in direct contact with the second dielectric layer. 
     
     
         20 . The fin field effect transistor device structure as claimed in  claim 15 , wherein the top portion of the via structure is in direct contact with the second dielectric layer.