Alkaline composition for copper electroplating comprising a grain refiner

Abstract

Described herein is a composition for depositing copper on a semiconductor substrate, the composition including(a) copper ions;(b) a grain refiner of formula G1or salts thereof(c) a complexing agent; and(d) optionally a buffer or a base capable of adjusting the pH to a pH of from 7 to 13;where the variables are as defined herein; andwhere the pH of the composition is from 7 to 13.

1 . A composition for depositing copper on a semiconductor substrate, the composition comprising:
 (a) copper ions;   (b) a grain refiner of formula G2a, G2b, or salts thereof:   
       
         
           
           
               
               
           
         
       
       wherein
 R G21  is selected from the group consisting of one or more H, C 1  to C 3  alkyl, C 1  to C 4  alkoxy, halogen, and CN; 
 R G22  is selected from the group consisting of one or more H, C 1  to C 4  alkyl, C 1  to C 6  alkoxy, halogen, and CN; and 
 X G1  is methandiyl, ethanediyl, propanediyl or butanediyl; 
 (c) a complexing agent; and 
 (d) optionally a buffer or a base capable of adjusting the pH to a pH of from 7 to 13; 
 wherein the pH of the composition is from 7 to 13; 
 wherein the composition further comprises a defect reducing agent of formula S1: 
 
       
         
           
           
               
               
           
         
       
       or salts thereof, 
       wherein
 R S1  is X S —Y S ; 
 R S2  is selected from the group consisting of R S1  and R S3 ; 
 X S  is selected from the group consisting of linear or branched C 1  to C 10  alkanediyl, linear or branched C 2  to C 10  alkenediyl, linear or branched C 2  to C 10  alkynediyl, and —X S6 —(O—C 2 H 3 R S6 ) m —; 
 Y S  is selected from the group consisting of OR S3 , NR S3 R S4 , N + R S3 R S4 R S5  and NH—(C═O)—R S3 ; 
 R S3 , R S4 , R S5  are the same or different and are selected from the group consisting of (i) H, (ii) C 5  to C 20  aryl, (iii) C 1  to C 10  alkyl (iv) C 6  to C 20  arylalkyl, (v) C 6  to C 20  alkylaryl, which may be substituted by OH, SO 3 H, COOH or a combination thereof, and
 (vi) —(C 2 H 3 R S6 —O) n —R S6 , and wherein R S3  and R S4  may together form a ring system, which may be interrupted by O or NR S7 ; 
 
 X S6  is C 1  to C 6  alkanediyl; 
 m, n are integers independently selected from the group consisting of 1 to 30; 
 R S6  is selected from the group consisting of H and C 1  to C 5  alkyl; 
 R S7  is selected from the group consisting of R S6  and 
 
       
         
           
           
               
               
           
         
       
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The composition according to  claim 1 , wherein the grain refiner is 3-carboxy-1-phenylmethylpyridinium. 
     
     
         5 . The composition according to  claim 1 , wherein
 R G1  is selected from the group consisting of one or more H, C 1  to C 4  carboxyl, C 1  to C 4  alkyl, C 1  to C 6  alkoxy, halogen, and CN;   R G2  is selected from the group consisting of one or more H, C 1  to C 4  carboxyl, C 1  to C 4  alkyl, C 1  to C 6  alkoxy, halogen, and CN; and   X G1  is a group —X G11 —C(O)—O—)—X G12 ;   X G11 , X G12  are independently selected from the group consisting of C 1  to C 4  alkandiyl.   
     
     
         6 . The composition according to  claim 1 , wherein the grain refiners are compounds of formula G3a, G3b, G3c, or salts thereof 
       
         
           
           
               
               
           
         
       
       wherein
 R G31  is selected from the group consisting of one or more H, C 1  to C 4  carboxyl, C 1  to C 4  alkyl, C 1  to C 6  alkoxy, halogen, and CN; 
 R G32  is selected from the group consisting of one or more H, C 1  to C 4  carboxyl, C 1  to C 4  alkyl, C 1  to C 6  alkoxy, C 1  to C 6  carboxy, halogen, and CN; and 
 X G32  is selected from the group consisting of a chemical bond or C 1  to C 4  alkandiyl. 
 
     
     
         7 . The composition according to  claim 6 , wherein the grain refiners are 4-(Methoxycarbonyl)benzyl pyridine-3-carboxylate and benzyl pyridine-3-carboxylate. 
     
     
         8 . (canceled) 
     
     
         9 . The composition according to  claim 1 , wherein the composition is free of any cyanide ions. 
     
     
         10 . The composition according to  claim 1 , which has a pH of 8 to 12. 
     
     
         11 . A method of using a composition according to  claim 1 , the method comprising using the composition for depositing copper on a semiconductor substrate comprising recessed features having an aperture size 50 nanometers or less. 
     
     
         12 . The method of use according to  claim 11 , wherein the recessed features have an aspect ratio of 4 or more. 
     
     
         13 . The method of use according to  claim 11 , wherein the semiconductor substrate is a dielectric substrate onto which a conducting seed layer is placed, wherein the seed layer consists of cobalt, iridium, osmium, palladium, platinum, rhodium, ruthenium, and alloys thereof. 
     
     
         14 . A process for depositing copper on a semiconductor substrate comprising a recessed feature having an aperture size of 50 nm or less, the recessed feature comprising a metal seed, the process comprising
 (a) bringing a composition according to  claim 1  into contact with the metal seed, and   (b) applying a current for a time sufficient to deposit a continuous seed of copper onto the metal seed of the recessed feature or to completely fill the recessed feature.   
     
     
         15 . The process according to  claim 14 , wherein the seed layer consists of cobalt, iridium, osmium, palladium, platinum, rhodium, ruthenium, molybdenum, and alloys thereof. 
     
     
         16 . The method of use according to  claim 11 , wherein the recessed features have an aperture size of 15 nm or less. 
     
     
         17 . The process according to  claim 14 , wherein the recessed feature has an aperture size of 15 nm or less. 
     
     
         18 . The process according to  claim 14 , wherein the seed layer consists of cobalt.