SILVER-BASED TRANSPARENT CONDUCTIVE LAYERS INTERFACED WITH COPPER TRACES AND METHODS FOR FORMING THE STRUCTURES
A method is described for method for patterning a metal layer interfaced with a transparent conductive film, in which the method comprises contacting a structure through a patterned mask with an etching solution comprising Fe +3 ions, wherein the structure comprises the metal layer comprising copper, nickel, aluminum or alloys thereof covering at least partially a transparent conductive film with conductive elements comprising silver, to expose a portion of the transparent conductive film. Etching solutions and the etched structures are also described.
1 . A method for patterning a metal layer interfaced with a transparent conductive film, the method comprising:
contacting a structure through a patterned mask with an etching solution comprising Fe +3 ions, wherein the the structure comprises the metal layer comprising copper, nickel, aluminum or alloys thereof covering at least partially a transparent conductive film with conductive elements comprising silver, to expose a portion of the transparent conductive film.
2 . The method of claim 1 wherein the etching solution comprises water and from about 0.001M to about 0.25M Fe +3 .
3 . The method of claim 2 wherein the etching solution further comprises a strong acid at a concentration from about 0.0001M to about 0.1M.
4 . The method of claim 2 wherein the etching solution further comprises from 0.001 to about 0.5 wt % non-ionic surfactant.
5 . The method of claim 2 wherein the etching solution further comprises from 0.001M to about 0.25M Fe +2 .
6 . The method of claim 1 wherein the etching solution has from about 0.005M to about 0.05M Fe +3 , from about 0.0025 wt % to about 0.1 wt % non-ionic surfactant, and the strong acid at a concentration from about 0.00025M to about 0.03M, wherein the strong acid is nitric acid and the anions balancing the iron cations are nitrate anions.
7 . The method of claim 1 wherein the transparent conductive film comprises a fused metal nanostructured network with a polymer overcoat having an average thickness from about 25 nm to about 500 nm.
8 . The method of claim 1 wherein the contacting comprises immersion of the structure in the etching solution for a selected period of time, and the method further comprising rising the structure following completion of the immersion.
9 . The method of claim 1 wherein the contacting comprises depositing the etching solution over the patterned mask, and the method further comprising depositing a rinse solution over the patterned mask at the completion of the etching process.
10 . The method of claim 1 wherein the patterned mask comprises photoresist and the pattern is formed using photolithography.
11 . The method of claim 1 further comprising patterning the transparent conductive film after etching the metal layer.
12 . The method of claim 11 wherein the patterning of the conductive film is performed using TCTF.
13 . The method of claim 1 wherein the metal layer comprises a layer of copper covered with a layer of nickel or aluminum.
14 . The method of claim 1 wherein following patterning the structure comprises a polymer substrate, a transparent conductive film covering at least part of a surface of the polymer substrate and metal traces confined to at least a portion of a bezel region along a border of the surface, wherein elements of the transparent conductive film are in electrical contact with portion of the metal trace to form a conduction pathway through the transparent conductive film, wherein the transparent conductive film has a sheet resistance of no more than 95 ohms/sq.
15 . A patterned film comprising a polymer substrate, a transparent conductive film covering at least part of a surface of the polymer substrate and metal traces confined to at least a portion of a bezel region along a border of the surface, wherein elements of the transparent conductive film are in electrical contact with portion of the metal trace to form a conduction pathway through the transparent conductive film, wherein the transparent conductive film has a sheet resistance of no more than 95 ohms/sq, and wherein the metal traces have a configuration of an etched material.
16 . The patterned film of claim 15 wherein the metal traces comprise a layer of copper having a thickness from about 100 nm to about 1 micron and wherein the top surfaces of the copper traces have a layer of nickel, aluminum or an alloy thereof.
17 . The patterned film of claim 15 wherein the copper traces have features with a resolution of no more than about 5 microns.
18 . An etching solution consisting essentially of water, from about 0.001M to about 0.25M Fe +3 , strong acid at a concentration from about 0.0001M to about 0.1M, optionally from 0.001 wt % to about 0.5 wt % surfactant, and optionally from 0 to about 0.25M Fe +2 , along with selected anions for charge balance of the listed cations.
19 . The etching solution of claim 18 wherein the strong acid is nitric acid and the anions balancing the iron cations comprise nitrate anions.
20 . The etching solution of claim 18 having from about 0.0025 wt % to about 0.1 wt % non-ionic surfactant.
21 . The etching solution of claim 18 having from about 0.005M to about 0.05M Fe +3 .
22 . The etching solution of claim 18 having from about 0.005M to about 0.05M Fe +3 , from about 0.0025 wt % to about 0.1 wt % non-ionic surfactant, and the strong acid at a concentration from about 0.00025M to about 0.03M, wherein the strong acid is nitric acid and the anions balancing the iron cations are nitrate anions.