Integration of ALD tantalum nitride for copper metallization

Abstract

A method and apparatus for depositing a tantalum nitride barrier layer is provided for use in an integrated processing tool. The tantalum nitride is deposited by atomic layer deposition. The tantalum nitride is removed from the bottom of features in dielectric layers to reveal the conductive material under the deposited tantalum nitride. Optionally, a tantalum layer may be deposited by physical vapor deposition after the tantalum nitride deposition. Optionally, the tantalum nitride deposition and the tantalum deposition may occur in the same processing chamber.

1 . A method of forming a metal interconnect on a semiconductor substrate, comprising; 
 depositing a tantalum nitride barrier layer by atomic layer deposition in a first process chamber;    depositing a second barrier layer over the tantalum nitride barrier layer in a second process chamber;    plasma etching the second barrier layer and the tantalum nitride barrier layer in a third process chamber; and    depositing a seed layer over exposed conductive material and the second barrier layer in a fourth processing chamber,    wherein the first processing chamber, the second processing chamber, the third processing chamber, and the fourth processing chamber are located in an integrated tool.    
   
   
       2 . The method of  claim 1 , wherein the tantalum nitride deposition is performed with a tantalum containing precursor selected from the group consisting of t-butylimino-tris(diethylamino)tantalum, pentakis (ethylmethylamino)tantalum, pentakis(dimethylamino)tantalum, pentakis (diethylamino)tantalum, t-butyliminotris(diethyl methylamino)tantalum, t-butylimino-tris(dimethylamino)tantalum, bis(cyclopentadienyl)tantalum trihydride, and bis(methylcyclopentadienyl) tantalum trihydride.  
   
   
       3 . The method of  claim 1 , wherein the tantalum nitride deposition is performed with a nitrogen containing precursor selected from the group consisting of ammonia, hydrazine, methylhydrazine, dimethylhydrazine, t-butylhydrazine, phenylhydrazine, azoisobutane, and ethylazide.  
   
   
       4 . The method of  claim 1 , wherein the plasma etching is performed with a gas selected from the group consisting of argon, nitrogen, and hydrogen.  
   
   
       5 . The method of  claim 1 , wherein the plasma etching is performed with a directional argon plasma.  
   
   
       6 . The method of  claim 1 , further comprising depositing additional metal by physical vapor deposition on the second barrier layer.  
   
   
       7 . The method of  claim 6 , further comprising depositing a bulk metal layer.  
   
   
       8 . The method of  claim 6 , wherein the additional metal is selected from the group consisting of copper, copper aluminum, copper tin, tantalum, tungsten, thallium, cobalt, titanium, and aluminum.  
   
   
       9 . The method of  claim 1 , wherein the third and fourth process chambers are the same chamber.  
   
   
       10 . The method of  claim 1 , wherein the fourth and fifth process chambers are the same chamber.  
   
   
       11 . The method of  claim 1 , wherein the seed layer is deposited by a method selected from the group consisting of chemical vapor deposition, physical vapor deposition, electroplating, and electroless plating.  
   
   
       12 . The method of  claim 1 , wherein the seed layer comprises a metal selected from the group consisting of copper, copper aluminum, copper tin, tantalum, tungsten, thallium, cobalt, titanium, and aluminum.  
   
   
       13 . The method of  claim 1 , further comprising a preliminary substrate surface cleaning with nitrogen before cleaning features formed in a dielectric layer and exposing a conductive material underlying the dielectric layer by generating a plasma in a remote plasma source, delivering radicals from the plasma to a first process chamber which contains the substrate, and contacting the features formed in the dielectric layer with the radicals prior to a barrier layer deposition.  
   
   
       14 . A method of forming a metal interconnect on a semiconductor substrate, comprising; 
 cleaning features formed in a dielectric layer and exposing a conductive material underlying the dielectric layer by generating a plasma in a remote plasma source, delivering radicals from the plasma to a first process chamber which contains the substrate, and contacting the features formed in the dielectric layer with the radicals prior to a barrier layer deposition;    depositing a tantalum nitride barrier layer by atomic layer deposition in a second process chamber;    depositing a second barrier layer by physical vapor deposition over the tantalum nitride barrier layer in a third process chamber;    optionally depositing additional tantalum or copper by physical vapor deposition on the second barrier layer; and    depositing a seed layer over the conductive material and the second barrier layer in a fourth processing chamber,    wherein the first processing chamber, the second processing chamber, the third processing chamber, and the fourth processing chamber are located in an integrated tool.    
   
   
       15 . The method of  claim 14 , wherein the cleaning is performed with a feed gas consisting of 0 to about 10 percent hydrogen and about 90 to 100 percent helium.  
   
   
       16 . The method of  claim 14 , wherein the tantalum nitride barrier deposition is performed with a tantalum containing precursor selected from the group consisting of t-butylimino-tris(diethylamino)tantalum, pentakis (ethylmethylamino)tantalum, pentakis(dimethylamino)tantalum, pentakis (diethylamino)tantalum, t-butyliminotris(diethyl methylamino)tantalum, t-butylimino-tris(dimethylamino)tantalum, bis(cyclopentadienyl)tantalum trihydride, and bis(methylcyclopentadienyl) tantalum trihydride.  
   
   
       17 . The method of  claim 14 , wherein the tantalum nitride barrier deposition is performed with a nitrogen containing precursor selected from the group consisting of ammonia, hydrazine, methylhydrazine, dimethylhydrazine, t-butylhydrazine, phenylhydrazine, azoisobutane, and ethylazide.  
   
   
       18 . The method of  claim 14 , further comprising depositing additional metal by physical vapor deposition on the second barrier layer.  
   
   
       19 . The method of  claim 18 , further comprising depositing a bulk metal layer.  
   
   
       20 . The method of  claim 14 , wherein the metal is selected from the group consisting of copper, copper aluminum, copper tin, tantalum, tungsten, thallium, cobalt, titanium, and aluminum.