Aqueous composition for etching of copper and copper alloys

Abstract

The present invention relates to an aqueous composition and a process for etching of copper and copper alloys. The aqueous composition comprises Fe 3+ ions, an acid and a N-alkoxylated polyamide. The aqueous composition is particularly useful for making of fine structures in the manufacture of printed circuit boards, IC substrates and the like.

1 . An aqueous composition for etching of copper and copper alloys comprising 1 to 100 g/l Fe 3+  ions, 10 to 400 g/l of at least one acid and 0.001 to 10 g/l of at least one etching additive selected from N-alkoxylated polyamides. 
     
     
         2 . The aqueous composition for etching of copper and copper alloys according to  claim 1  wherein the N-alkoxylated polyamide is obtained by N-alkoxylation of a polyamide with one or more compounds of formula (I), 
       
         
           
           
               
               
           
         
         wherein R 1  is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms and R 2  is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms. 
       
     
     
         3 . The aqueous composition for etching of copper and copper alloys according to  claim 2  wherein R1 and R2 in formula (I) independently are hydrogen or methyl. 
     
     
         4 . The aqueous composition for etching of copper and copper alloys according to  claim 1  wherein the N-alkoxylated polyamide is obtained by polymerization of a N-alkoxylated lactam according to formula (II) 
       
         
           
           
               
               
           
         
         wherein 
         R 3  is selected from the group consisting of hydrogen and methyl, 
         A is a hydrocarbon residue, 
         n is a whole number from 2 to 10 and m is a whole number from 1 to 50. 
       
     
     
         5 . The aqueous composition for etching of copper and copper alloys according to  claim 4  wherein the N-alkoxylated lactam according to formula (II) is selected from the group consisting of ethoxylated beta-lactam, hexaethoxylated gamma-butyrolactam, octaethoxylated delta-valerolactam, pentapropoxylated delta-valerolactam, hexaethoxylated epsilon-caprolactam and dodecaethoxylated epsilon-caprolactam. 
     
     
         6 . The aqueous composition for etching of copper and copper alloys according to  claim 1  wherein the at least one acid comprises one or both of sulfuric acid and methanesulfonic acid. 
     
     
         7 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 a. providing a substrate having a copper or copper alloy surface,   b. contacting said substrate with the aqueous composition according to  claim 1  in a first tank wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition,   c. transferring a portion of said aqueous composition after contacting with the substrate to a second tank wherein said second tank comprises an anode and a cathode and   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         8 . The aqueous composition for etching of copper and copper alloys according to  claim 2  wherein the N-alkoxylated polyamide is obtained by polymerization of a N-alkoxylated lactam according to formula (II) 
       
         
           
           
               
               
           
         
         wherein 
         R 3  is selected from the group consisting of hydrogen and methyl, 
         A is a hydrocarbon residue, 
         n is a whole number from 2 to 10 and m is a whole number from 1 to 50. 
       
     
     
         9 . The aqueous composition for etching of copper and copper alloys according to  claim 3  wherein the N-alkoxylated polyamide is obtained by polymerization of a N-alkoxylated lactam according to formula (II) 
       
         
           
           
               
               
           
         
         wherein 
         R 3  is selected from the group consisting of hydrogen and methyl, 
         A is a hydrocarbon residue, 
         n is a whole number from 2 to 10 and m is a whole number from 1 to 50. 
       
     
     
         10 . The aqueous composition for etching of copper and copper alloys according to  claim 8  wherein the N-alkoxylated lactam according to formula (II) is selected from the group consisting of ethoxylated beta-lactam, hexaethoxylated gamma-butyrolactam, octaethoxylated delta-valerolactam, pentapropoxylated delta-valerolactam, hexaethoxylated epsilon-caprolactam and dodecaethoxylated epsilon-caprolactam. 
     
     
         11 . The aqueous composition for etching of copper and copper alloys according to  claim 9  wherein the N-alkoxylated lactam according to formula (II) is selected from the group consisting of ethoxylated beta-lactam, hexaethoxylated gamma-butyrolactam, octaethoxylated delta-valerolactam, pentapropoxylated delta-valerolactam, hexaethoxylated epsilon-caprolactam and dodecaethoxylated epsilon-caprolactam. 
     
     
         12 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 d. providing a substrate having a copper or copper alloy surface,   e. contacting said substrate with the aqueous composition according to  claim 2  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   f. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         13 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 g. providing a substrate having a copper or copper alloy surface,   h. contacting said substrate with the aqueous composition according to  claim 3  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   i. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         14 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 j. providing a substrate having a copper or copper alloy surface,   k. contacting said substrate with the aqueous composition according to  claim 4  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   l. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         15 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 m. providing a substrate having a copper or copper alloy surface,   n. contacting said substrate with the aqueous composition according to  claim 6  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   o. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         16 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 p. providing a substrate having a copper or copper alloy surface,   q. contacting said substrate with the aqueous composition according to  claim 6  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   r. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         17 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 s. providing a substrate having a copper or copper alloy surface,   t. contacting said substrate with the aqueous composition according to  claim 8  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   u. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         18 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 v. providing a substrate having a copper or copper alloy surface,   w. contacting said substrate with the aqueous composition according to  claim 9  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   x. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         19 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 y. providing a substrate having a copper or copper alloy surface,   z. contacting said substrate with the aqueous composition according to  claim 10  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   aa. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.   
     
     
         20 . A process for etching of copper and copper alloys comprising, in this order, the steps of
 bb. providing a substrate having a copper or copper alloy surface,   cc. contacting said substrate with the aqueous composition according to  claim 11  in a first tank
 wherein during contacting copper is oxidized to Cu 2+  ions and the Cu 2+  ions are dissolved in said aqueous composition, 
   dd. transferring a portion of said aqueous composition after contacting with the substrate to a second tank
 wherein said second tank comprises an anode and a cathode and 
   d. reducing said Cu 2+  ions to copper by applying a current between said anode and said cathode.