Process for forming cobalt and cobalt silicide materials in tungsten contact applications

Abstract

Embodiments of the invention described herein generally provide methods for forming cobalt silicide layers and metallic cobalt layers by using various deposition processes and annealing processes. In one embodiment, a method for forming a metallic silicide containing material on a substrate is provided which includes forming a metallic silicide material over a silicon-containing surface during a vapor deposition process by sequentially depositing a plurality of metallic silicide layers and silyl layers on the substrate, depositing a metallic capping layer over the metallic silicide material, heating the substrate during an annealing process, and depositing a metallic contact material over the barrier material. In one example, the metallic silicide layers and the metallic capping layer both contain cobalt. The cobalt silicide material may contain a silicon/cobalt atomic ratio of about 1.9 or greater, such as greater than about 2.0, or about 2.2 or greater.

1 . A method for forming a cobalt silicide containing material on a substrate, comprising:
 exposing a substrate to at least one preclean process to expose a silicon-containing surface;   depositing a cobalt silicide material over the silicon-containing surface;   depositing a metallic cobalt material over the cobalt silicide material; and   depositing a metallic tungsten material over the metallic cobalt material.   
   
   
       2 . The method of  claim 1 , wherein the cobalt silicide material is deposited by exposing the substrate to a cobalt precursor and a silicon precursor during a chemical vapor deposition process or an atomic layer deposition process. 
   
   
       3 . The method of  claim 2 , wherein the cobalt silicide material comprises a silicon/cobalt atomic ratio of about 1.9 or greater. 
   
   
       4 . The method of  claim 3 , wherein the silicon/cobalt atomic ratio is about 2.2 or greater. 
   
   
       5 . The method of  claim 1 , wherein the deposition of the metallic tungsten material comprises forming a tungsten-containing seed layer and forming a tungsten-containing bulk layer thereon. 
   
   
       6 . The method of  claim 1 , further comprising depositing a barrier material over the metallic cobalt material and depositing the metallic tungsten material over the barrier layer. 
   
   
       7 . The method of  claim 2 , wherein the cobalt precursor comprises the general chemical formula (CO) x Co y L z , wherein:
 X is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12;   Y is 1, 2, 3, 4, or 5;   Z is 1, 2, 3, 4, 5, 6, 7, or 8; and   L is a ligand independently selected from the group consisting of cyclopentadienyl, alkylcyclopentadienyl, methylcyclopentadienyl, pentamethylcyclopentadienyl, pentadienyl, alkylpentadienyl, cyclobutadienyl, butadienyl, allyl, ethylene, propylene, alkenes, dialkenes, alkynes, nitrosyl, ammonia, derivatives thereof, and combinations thereof.   
   
   
       8 . The method of  claim 2 , wherein the cobalt precursor comprises a cyclopentadienyl cobalt bis(carbonyl). 
   
   
       9 . The method of  claim 1 , wherein the cobalt silicide material is exposed to a hydrogen plasma prior to depositing the metallic cobalt material. 
   
   
       10 . The method of  claim 2 , wherein the cobalt silicide material is deposited during the atomic layer deposition process by conducting a deposition cycle to deposit a cobalt silicide layer; and
 repeating the deposition cycle to form a plurality of the cobalt silicide layers, wherein the deposition cycle comprises exposing the substrate to a silicon-containing reducing gas comprising the silicon precursor while sequentially exposing the substrate to the cobalt precursor and a hydrogen plasma.   
   
   
       11 . The method of  claim 10 , wherein the substrate, the cobalt silicide material, or the metallic cobalt material is exposed to the silicon-containing reducing gas during a pre-soak process or a post-soak process. 
   
   
       12 . The method of  claim 11 , further comprising exposing the substrate to a plasma treatment during the pre-soak process or the post-soak process. 
   
   
       13 . The method of  claim 1 , wherein the cobalt silicide material is deposited during a pulsed chemical vapor deposition process by conducting a deposition cycle to deposit a cobalt silicide layer; and
 repeating the deposition cycle to form a plurality of the cobalt silicide layers, wherein the deposition cycle comprises exposing the substrate to a silicon precursor, a cobalt precursor, hydrogen gas, and a plasma.   
   
   
       14 . A method for forming a metallic silicide containing material on a substrate, comprising:
 exposing a substrate to at least one preclean process to expose a silicon-containing surface;   forming a metallic silicide material over the silicon-containing surface during a vapor deposition process comprising sequentially depositing a plurality of metallic silicide layers and silyl layers on the substrate;   depositing a metallic capping layer over the metallic silicide material;   heating the substrate during an annealing process; and   depositing a metallic contact material over the barrier material.   
   
   
       15 . The method of  claim 14 , wherein the metallic silicide material comprises a gradient silicon concentration decreasing from the silicon-containing surface towards the metallic capping layer. 
   
   
       16 . The method of  claim 14 , wherein the metallic silicide layers and the metallic capping layer comprise the same metal. 
   
   
       17 . The method of  claim 16 , wherein the metallic silicide layers and the metallic capping layer comprise cobalt the metallic contact material comprises tungsten. 
   
   
       18 . The method of  claim 14 , wherein the metallic silicide material comprises a silicon/cobalt atomic ratio of about 1.9 or greater. 
   
   
       19 . The method of  claim 18 , wherein the silicon/cobalt atomic ratio is about 2.2 or greater. 
   
   
       20 . The method of  claim 14 , wherein the metallic silicide layers are deposited by a chemical vapor deposition process or an atomic layer deposition process. 
   
   
       21 . The method of  claim 20 , wherein the metallic silicide material comprises at least one element selected from the group consisting of cobalt, nickel, platinum, palladium, rhodium, titanium, and combinations thereof. 
   
   
       22 . The method of  claim 21 , wherein the metallic silicide material comprises titanium silicide. 
   
   
       23 . The method of  claim 21 , wherein the metallic silicide layers are exposed to a silicon-containing reducing gas and a plasma while depositing the silyl layers thereon. 
   
   
       24 . A method for forming a cobalt silicide containing material on a substrate, comprising:
 exposing a substrate to at least one preclean process to expose a silicon-containing surface;   forming a cobalt silicide material over the silicon-containing surface during a vapor deposition process comprising sequentially depositing a plurality of cobalt silicide layers and silyl layers on the substrate, wherein the cobalt silicide material comprises a silicon/cobalt atomic ratio of about 1.9 or greater;   depositing a metallic cobalt capping layer over the cobalt silicide material;   heating the substrate during an annealing process; and   depositing a tungsten contact material over the barrier material.   
   
   
       25 . The method of  claim 24 , wherein the silicon/cobalt atomic ratio is about 2.2 or greater.