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 structure comprising a metal layer interfaced with a transparent conductive film, the method comprising:
contacting the metal layer through a patterned mask with an etching solution comprising Fe +3 ions and nitric acid, the metal layer comprising copper, nickel, aluminum or alloys thereof, the transparent conductive film comprising conductive elements comprising silver,
thereby etching the metal layer 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 nitric acid is 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 comprises from about 0.005M to about 0.05M Fe +3 , from about 0.0025 wt % to about 0.1 wt % non-ionic surfactant, and nitric acid at a concentration from about 0.00025M to about 0.03M, wherein anions balancing iron cations are nitrate anions.
7 . The method of claim 1 wherein the transparent conductive film comprises a fused silver 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 rinsing 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 having a pattern 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 transparent conductive transfer film technology.
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 a portion of the metal traces 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 . The method of claim 14 wherein the transparent conductive film is significantly excluded from the bezel region.
16 . The method of claim 14 wherein the bezel region has a width of less than about 5 mm.
17 . The method of claim 14 wherein the transparent conductive film has a transmittance of at least about 90% and a haze of no more than about 1%.
18 . The method of claim 14 wherein a plurality of electrical contact points exist between the elements of the transparent conductive film and the metal traces.
19 . The method of claim 14 wherein the structure further comprises a photosensitive resin layer between the transparent conductive film and the polymer substrate.
20 . The method of claim 19 , the method further comprising exposing the structure to patterned light to selectively etch the transparent conductive film.