Method of forming a composite conductive film

• US 10,234,969 B2
• Filed: 04/24/2017
• Issued: 03/19/2019
• Est. Priority Date: 07/29/2011
• Status: Active Grant

• Current Assignee: Sinovia Technologies, Inc.
• Original Assignee: Sinovia Technologies, Inc.
• Inventors: Gaynor, Whitney, Burkhard, George
• Primary Examiner(s): Yuan, Dah-Wei D.
• Assistant Examiner(s): Hernandez-Diaz, Jose
• Application Number:
  US15/494,800
• Publication Number:
  US 20170228055A1
• Time in Patent Office: 694 Days
• CPC Class Codes: B05D 3/007 After-treatment
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G03F 1/24 Reflection masks; Preparation thereof
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: G03F 7/0047 characterised by additives for obtaining a metallic or ceramic pattern, e.g. by firing
• CPC Class Codes: G03F 7/038 Macromolecular compounds which are rendered insoluble or differentially wettable G03F7/075 takes precedence; macromolecular azides G03F7/012; macromolecular diazonium compounds G03F7/021
• CPC Class Codes: G03F 7/0388 with ethylenic or acetylenic bands in the side chains of the photopolymer
• CPC Class Codes: G03F 7/161 using a previously coated surface, e.g. by stamping or by transfer lamination
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H01B 1/16 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 13/0013 for embedding wires in plastic layers
• CPC Class Codes: H01B 5/14 comprising conductive layers or films on insulating-supports
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 1/0274 : Optical details, e.g. printed circuits comprising integral optical means H05K1/0269 takes precedence; coupling light guides with opto-electronic components G02B6/42
• CPC Class Codes: H05K 1/036 : Multilayers with layers of different types
• CPC Class Codes: H05K 1/09 : Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 2201/0108 : Transparent
• CPC Class Codes: H05K 2201/0137 : Materials
• CPC Class Codes: H05K 2203/10 : Using electric, magnetic and electromagnetic fields; Using laser light
• CPC Class Codes: H05K 3/103 : by bonding or embedding conductive wires or strips
• CPC Class Codes: H10K 30/821 : comprising carbon nanotubes
• CPC Class Codes: H10K 50/805 : Electrodes
• CPC Class Codes: Y10T 428/24355 : Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 442/10 : Scrim [e.g., open net or mesh, gauze, loose or open weave or knit, etc.]
• CPC Class Codes: Y10T 442/188 : Metal or metal-coated fiber-containing scrim
• CPC Class Codes: Y10T 442/191 : Inorganic fiber-containing scrim

Abstract

A method of fabricating a composite conductive film is provided. The method includes providing, as a matrix, a layer of cross-linkable polymer, where the cross-linkable polymer is in a non-cross-linked state. The method further includes introducing inorganic nanowires upon a surface of the layer of cross-linkable polymer. The inorganic nanowires are, in isolated form, characterized by a first conductivity stability temperature. The method further includes embedding at least some of the inorganic nanowires into the layer of cross-linkable polymer to form an inorganic mesh, thereby forming the composite conductive film. The method further includes cross-linking the polymer within a surface portion of the composite conductive film. Cross-linking the polymer within the surface portion of the composite conductive film results in the surface portion having a second conductivity stability temperature that is greater than the first conductivity stability temperature.

Claims

1. A method of fabricating a composite conductive film, comprising:

providing, as a matrix, a layer of cross-linkable material, wherein the layer of the cross-linkable material has a surface and is in a non-cross-linked state;

applying a plurality of inorganic nanowires to a surface of a sacrificial superstrate, wherein the inorganic nanowires are, in isolated form, characterized by a first conductivity stability temperature;

embedding at least some of the plurality of inorganic nanowires into the layer of cross-linkable material to form an inorganic mesh within the layer of cross-linkable material, thereby forming the composite conductive film, wherein embedding the at least some of the plurality of inorganic nanowires into the layer of the cross-linkable material comprises;

laminating the surface of the sacrificial superstrate to the surface of the layer of the cross-linkable material, wherein the layer of the cross-linkable material is in a liquid state when the surface of the sacrificial superstrate is laminated to the surface of the layer of the cross-linkable material;

while the surface of the sacrificial substrate is laminated to the surface of the layer of the cross-linkable material, cross-linking the cross-linkable material within at least a surface portion of the composite conductive film, wherein following the cross-linking, the cross-linkable material within at least the surface portion of the composite conductive film is in a cross-linked state; and

after cross-linking the cross-linkable material within at least a surface portion of the composite conductive film, removing the sacrificial superstrate;

wherein cross-linking the cross-linkable material within at least the surface portion of the composite conductive film results in at least the surface portion of the composite conductive film having a second conductivity stability temperature that is greater than the first conductivity stability temperature;

wherein, prior to the cross-linking, the cross-linkable material comprises monomers and/or oligomers; and

wherein the composite conductive film is characterized by a sheet resistance having a temperature coefficient that is less than 0.002 (Ω

K)<sup>−

1</sup> between the first conductivity stability temperature and the second conductivity stability temperature.

2. The method of claim 1, wherein the plurality of nanowires has an average aspect ratio between 10-1000.

3. The method of claim 1, wherein the layer of cross-linkable material comprises one of an acrylated polyurethane or an epoxy-based alkyl-amine.

4. The method of claim 1, wherein providing, as the matrix, the layer of cross-linkable material includes depositing the layer of cross-linkable material on a second substrate different from the sacrificial substrate.

5. The method of claim 4, wherein the second substrate is one of a polyester substrate or a borosilicate glass substrate.

6. The method of claim 1, wherein the layer of cross-linkable material undergoes cross-linking when exposed to one of ultraviolet (UV) radiation, heat treatment, or a chemical catalyst.

7. The method of claim 1, wherein laminating the surface of the sacrificial superstrate to the surface of the layer of the cross-linkable material comprises:

applying a predefined pressure between the surface of the sacrificial superstrate and the surface of the layer of the cross-linkable material.