US 11,926,524 B1 · Methods, apparatus, and systems for fabricating solution-based conductive 2D and 3D electronic circuits

Abstract

This work develops a novel microfluidic method to fabricate conductive graphene-based 3D micro-electronic circuits on any solid substrate including, Teflon, Delrin, silicon wafer, glass, metal or biodegradable/non-biodegradable polymer-based, 3D microstructured, flexible films. It was demonstrated that this novel method can be universally applied to many different natural or synthetic polymer-based films or any other solid substrates with proper pattern to create graphene-based conductive electronic circuits. This approach also enables fabrication of 3D circuits of flexible electronic films or solid substrates. It is a green process preventing the need for expensive and harsh postprocessing requirements for other fabrication methods such as ink-jet printing or photolithography. We reported that it is possible to fill the pattern channels with different dimensions as low as 10×10 μm. The graphene nanoplatelet solution with a concentration of 60 mg/mL in 70% ethanol, pre-annealed at 75° C. for 3 h, provided ˜0.5-2 kOhm resistance. The filling of the pattern channels with this solution at a flow rate of 100 μL/min created a continuous conductive graphene pattern on flexible polymeric films. The amount of graphene used to coat 1 cm2 of area is estimated as ˜10 μg. A second method regarding the transfer of graphene material-based circuits with small features size (5 μm depth, 10 μm width) from any solid surface to flexible polymeric films via polymer solvent casting approach was demonstrated. This method is applicable to any natural/synthetic polymer and their respective organic/inorganic solvents.

Claims40

Dependent claims

A method of fabricating a conductive pattern or circuit in a substrate having a length, width, and thickness comprising:

a. providing a substrate with a predetermined pattern or circuit of three-dimensional structural features in the thickness of the substrate to create three-dimensional open or closed channels in directions of any of the length, width, and thickness of the substrate, the channels having surfaces, wherein the substrate is flexible and the predetermined pattern is formed directly into the flexible substrate without molds;
and
b. coating at least some of said channel surfaces of selected said channels with one or more layers, each layer created by:
i. controlling of flow of a viscous or solution-form liquid comprising a solute of electrically-conductive materials and a solvent through the selected said channels to control at least partial filling of the selected channels with the liquid by control of:
1. flow direction;
2. flow volume;
3. flow rate;
and
4. concentration of the electrically-conductive materials in the liquid;
and
ii. removing substantially the solvent;
c. to leave the one or more layers of the solute of the electrically-conductive materials at a controlled thickness and coverage of the surfaces of the selected said channels to create a conductive pattern or circuit based on the coating of the channels.

9 more elements

A method of fabricating a conductive pattern or circuit in a substrate having a length, width, and thickness comprising:

a. providing a substrate with a predetermined pattern or circuit of three-dimensional structural features in the thickness of the substrate to create three-dimensional open or closed channels in directions of any of the length, width, and thickness of the substrate, the channels having surfaces, (i) wherein the predetermined pattern or circuit is indirectly created in the substrate by (1) creating a mold comprising high resolution three-dimensional microstructural features with heights, widths and thicknesses on the order of several tens of micrometers to several hundreds of micrometers, and (2) creating a negative of the three-dimensional microstructural features of the mold from the mold to create the channels in the substrate, (ii) wherein the substrate comprises a film of a natural or synthetic polymeric material, wherein the film is formed by (1) casting a precursor solution onto the mold by direct pouring, drop casting, or spin casting, (2) dry phase inversion or pore forming agent leaching;
and (iii) removal from the mold;
and
b. coating at least some of said channel surfaces of selected said channels with one or more layers, each layer created by:
i. controlling of flow of a viscous or solution-form liquid comprising a solute of electrically-conductive materials and a solvent through the selected said channels to control at least partial filling of the selected channels with the liquid by control of:
1. flow direction;
2. flow volume;
3. flow rate;
and
4. concentration of the electrically-conductive materials in the liquid;
and
ii. removing substantially the solvent;
c. to leave the one or more layers of the solute of the electrically-conductive materials at a controlled thickness and coverage of the surfaces of the selected said channels to create a conductive pattern or circuit based on the coating of the channels.

10 more elements

A method of fabricating a conductive pattern or circuit in a substrate having a length, width, and thickness comprising:

a. providing a substrate with a predetermined pattern or circuit of three-dimensional structural features in the thickness of the substrate to create three-dimensional open or closed channels in directions of any of the length, width, and thickness of the substrate, the channels having surfaces;
and
b. coating at least some of said channel surfaces of selected said channels with one or more layers, each layer created by:
i. controlling of flow of a viscous or solution-form liquid comprising a solute of electrically-conductive materials and a solvent through the selected said channels to control at least partial filling of the selected channels with the liquid by control of:
1. flow direction;
2. flow volume;
3. flow rate;
and
4. concentration of the electrically-conductive materials in the liquid;
and
ii. removing substantially the solvent;
c. to leave the one or more layers of the solute of the electrically-conductive materials at a controlled thickness and coverage of the surfaces of the selected said channels to create a conductive pattern or circuit based on the coating of the channels;
d. further comprising transferring the conductive three-dimensional pattern or circuit to a second substrate by:
i. placing a polymer solution over the conductive three-dimensional pattern or circuit in the substrate;
ii. curing the polymer solution in place effective to;
1. create a second substrate;
2. promote adherence at least substantially of the conductive three-dimensional pattern to the second substrate;
and
iii. transferring the conductive three-dimensional pattern to the second substrate by separating the second substrate from the first substrate.

16 more elements

A method of fabricating a conductive pattern or circuit in a substrate having a length, width, and thickness comprising:

a. providing a substrate with a predetermined pattern or circuit of three-dimensional structural features in the thickness of the substrate to create three-dimensional open or closed channels in directions of any of the length, width, and thickness of the substrate, the channels having surfaces;
and
b. coating at least some of said channel surfaces of selected said channels with one or more layers, each layer created by:
i. controlling of flow of a viscous or solution-form liquid comprising a solute of electrically-conductive materials and a solvent through the selected said channels to control at least partial filling of the selected channels with the liquid by control of:
1. flow direction;
2. flow volume;
3. flow rate;
and
4. concentration of the electrically-conductive materials in the liquid;
and
ii. removing substantially the solvent;
c. to leave the one or more layers of the solute of the electrically-conductive materials at a controlled thickness and coverage of the surfaces of the selected said channels to create a conductive pattern or circuit based on the coating of the channels;
d. further comprising placing a cover over at least some of the channels in the substrate to create closed channels and either coating the selected channels:
i. before placement of the cover;
or
ii. after placement of the cover.

13 more elements

Dependencies are inferred from the claim text.

Methods, apparatus, and systems for fabricating solution-based conductive 2D and 3D electronic circuits

Life of this patent

Methods, apparatus, and systems for fabricating solution-based conductive 2D and 3D electronic circuits

Life of this patent

Abstract

Claims40