Plating bath and method

Abstract

Copper plating baths containing a leveling agent that is a reaction product of a certain imidazole with a certain epoxide-containing compound that deposit copper on the surface of a conductive layer are provided. Such plating baths deposit a copper layer that is substantially planar on a substrate surface across a range of electrolyte concentrations. Methods of depositing copper layers using such copper plating baths are also disclosed.

1 . A reaction product of one or more imidazole compounds with one or more epoxide-containing compounds; wherein at least one imidazole compound has the formula 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2  and R 3  are independently chosen from H, (C 1- C 12 )alkyl, (C 2 -C 12 )alkenyl and aryl and provided that R 1  and R 2  are not both H. 
     
     
         2 . The reaction product of  claim 1  wherein R 1 , R 2  and R 3  are independently chosen from H, (C 1- C 8 )alkyl, (C 2 -C 7 )alkenyl, or aryl. 
     
     
         3 . The reaction product of  claim 1  wherein the (C 1 -C 12 )alkyl groups and the (C 2 -C 12 )alkenyl groups are each substituted with one or more of hydroxyl groups, halogen, and aryl groups. 
     
     
         4 . The reaction product of  claim 1  wherein the epoxide-containing compound is chosen from compounds of the formulae 
       
         
           
           
               
               
           
         
       
       where Y, Y 1  and Y 2  are independently chosen from H and (C 1 -C 4 )alkyl; X=halogen; A=OR 4  or R 5 ; R 4 ═((CR 6 R 7 ) m O) n , (aryl-O) p , CR 6 R 7 —Z—CR 6 R 7 O or OZ 1   t O; R 5 ═(CH 2 ) y ; A1 is (C 5 -C 12 )cycloalkyl; Z=a 5- or 6-membered ring; Z 1  is R 12 OArOR 12 , (R 13 O) a Ar(OR 13 ) a , or (R 13 O) a Cy(OR 13 ) a ; Cy═(C 5 -C 12 )cycloalkyl; each R 6  and R 7  are independently chosen from H, CH 3  and OH; each R 11  represents (C 1 -C 4 )alkyl or (C 1 -C 4 )alkoxy; each R 12  represents (C 1 -C 8 )alkyl; each R 13  represents a (C 2 -C 6 )alkyleneoxy; each a=1-10; m=1-6; n=1-20; p=1-6; q=1-6; r=0-4; t=1-4; and y=0-6; wherein Y and Y 1  may be taken together to form a (C 8 -C 12 )cyclic compound. 
     
     
         5 . A copper electroplating bath comprising: a source of copper ions, an electrolyte, and a leveling agent, wherein the leveling agent is a reaction product of one or more imidazole compounds with one or more epoxide-containing compounds; wherein at least one imidazole compound has the formula 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2  and R 3  are independently chosen from H, (C 1- C 12 )alkyl, (C 2 -C 12 )alkenyl, and aryl and provided that R 1  and R 2  are not both H. 
     
     
         6 . The copper electroplating bath of  claim 5  wherein at least one of R 1  and R 2  is chosen from (C 1- C 8 )alkyl, (C 3- C 7 )alkenyl and aryl. 
     
     
         7 . The copper electroplating bath of  claim 6  wherein R 3  is H. 
     
     
         8 . The copper electroplating bath of  claim 5  wherein the epoxide-containing compound comprises from 1 to 3 epoxy groups. 
     
     
         9 . The copper electroplating bath of  claim 5  wherein the epoxide-containing compound is chosen from compounds of the formulae 
       
         
           
           
               
               
           
         
       
       where Y, Y 1  and Y 2  are independently chosen from H and (C 1 -C 4 )alkyl; X=halogen; A=OR 4  or R 5 ; R 4 ═((CR 6 R 7 ) m O) n , (aryl-O) p , CR 6 R 7 —Z—CR 6 R 7 O or OZ 1   t O; R 5 ═(CH 2 ) y ; A1 is (C 5 -C 12 )cycloalkyl; Z=a 5- or 6-membered ring; Z 1  is R 12 OArOR 12 , (R 13 O) a Ar(OR 13 ) a , or (R 13 O) a Cy(OR 13 ) a ; Cy=(C 5 -C 12 )cycloalkyl; each R 6  and R 7  are independently chose from H, CH 3  and OH; each R 11  represents (C 1 -C 4 )alkyl or (C 1 -C 4 )alkoxy; each R 12  represents (C 1 -C 8 )alkyl; each R 13  represents a (C 2 -C 6 )alkyleneoxy; each a=1-10; m=1-6; n=1-20; p=1-6; q=1-6; r=0-4; t=1-4; and y=0-6; wherein Y and Y 1  may be taken together to form a (C 8 -C 12 )cyclic compound. 
     
     
         10 . A method of depositing copper on a substrate comprising: contacting a substrate to be plated with copper into the copper electroplating bath of  claim 5 ; and applying a current density for a period of time sufficient to deposit a copper layer on the substrate.