Electroless copper plating solution

Abstract

The invention relates to an electroless aqueous copper plating solution, comprising a source of copper ions, a reducing agent or a source of a reducing agent, and a combination comprising i) N,N,N′,N′-Tetrakis (2-hydroxypropyl)ethylenediamine or a salt thereof, and ii) N′-(2-Hydroxyethyl)-ethylenediamine-N,N,N′-triacetic acid or a salt thereof, as complexing agents, as well as to a method for electroless copper plating utilizing said solution and the use of the solution for the plating of substrates.

1 . An electroless aqueous copper plating solution, comprising
 a source of copper ions,   a reducing agent or a source of a reducing agent, and   a combination comprising   i) N,N,N′,N′-Tetrakis (2-hydroxypropyl)ethylenediamine or a salt thereof, and   ii) N′-(2-Hydroxyethyl)-ethylenediamine-N,N,N′-triacetic acid or a salt thereof,   as complexing agents.   
     
     
         2 . The electroless aqueous copper plating solution according to  claim 1 , wherein the combination of complexing agents further comprises
 iii) ethylenediamine tetraacetic acid or a salt thereof.   
     
     
         3 . The electroless aqueous copper plating solution according to  claim 1 , wherein the ratio of the total molar amount of all complexing agents to copper ions is in the range of 1:1 to 8:1. 
     
     
         4 . The electroless aqueous copper plating solution according to  claim 1 , wherein the ratio of the molar amount of complexing agent i) to the molar amount of complexing agent ii) ranges from 1:0.05 to 1:20. 
     
     
         5 . The electroless aqueous copper plating solution according to  claim 2 , wherein the ratio of the molar amount of complexing agent i) to the molar amount of a mixture of complexing agent ii) and complexing agent iii) ranges from 1:0.05 to 1:20. 
     
     
         6 . The electroless aqueous copper plating solution according to  claim 1 , wherein the reducing agent is selected from glyoxylic acid and formaldehyde. 
     
     
         7 . A method for electroless copper plating, the method comprising contacting a substrate with an electroless aqueous copper plating solution according to  claim 1 . 
     
     
         8 . The method according to  claim 7 , wherein the substrate is a substrate made from glass, ceramic or plastics. 
     
     
         9 . The method according to  claim 7 , wherein the substrate is a glass panel. 
     
     
         10 . The method according to  claim 7 , wherein the substrate has a surface area of at least 5 m 2 . 
     
     
         11 . (canceled) 
     
     
         12 . The method according to  claim 7 , wherein on the substrate a copper layer with a thickness of 0.5 μm to 3 μm is produced. 
     
     
         13 . The method according to  claim 7 , wherein on the substrate a copper layer with a roughness, expressed as the root-mean-square roughness parameter, of 5 to 60 nm is produced. 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . The electroless aqueous copper plating solution according to  claim 2 , wherein the ratio of the total molar amount of all complexing agents to copper ions is in the range of 1:1 to 8:1. 
     
     
         18 . The electroless aqueous copper plating solution according to  claim 2 , wherein the ratio of the molar amount of complexing agent i) to the molar amount of complexing agent ii) ranges from 1:0.05 to 1:20. 
     
     
         19 . The electroless aqueous copper plating solution according to  claim 3 , wherein the ratio of the molar amount of complexing agent i) to the molar amount of complexing agent ii) ranges from 1:0.05 to 1:20. 
     
     
         20 . The electroless aqueous copper plating solution according to  claim 17 , wherein the ratio of the molar amount of complexing agent i) to the molar amount of a mixture of complexing agent ii) and complexing agent iii) ranges from 1:0.05 to 1:20. 
     
     
         21 . The electroless aqueous copper plating solution according to  claim 2 , wherein the reducing agent is selected from glyoxylic acid and formaldehyde. 
     
     
         22 . A method for electroless copper plating, the method comprising contacting a substrate with an electroless aqueous copper plating solution according to  claim 2 .