ELECTROLESS COPPER PLATING SOLUTION
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 .