Process for making self-patterning substrates and the product thereof

• US 8,747,599 B2
• Filed: 08/22/2008
• Issued: 06/10/2014
• Est. Priority Date: 05/29/2008
• Status: Expired due to Fees

• Current Assignee: Chidella Krishna Sastry, Chidella Venkata Krishna Mohan Sharma, Srinivas Tangirala
• Original Assignee: Chidella Krishna Sastry, Chidella Venkata Krishna Mohan Sharma, Srinivas Tangirala
• Inventors: Sastry, Chidella Krishna, Sharma, Chidella Venkata Krishna Mohan, Tangirala, Srinivas
• Primary Examiner(s): Osele, Mark A
• Assistant Examiner(s): HARM, NICKOLAS R
• Application Number:
  US12/230,055
• Publication Number:
  US 20090297802A1
• Time in Patent Office: 2,118 Days
• Field of Search: 427/58, 427/96.1, 427/98.4, 427/523, 427/525, 427/529, 427/530, 427/531
• US Class Current: 156/242
• CPC Class Codes: C23C 18/08 characterised by the deposition of metallic material
• CPC Class Codes: C23C 18/1608 from pretreatment step, i.e. selective pre-treatment
• CPC Class Codes: C23C 18/165 Multilayered product layered product B32B
• CPC Class Codes: C23C 26/00 Coating not provided for in groups C23C2/00 - C23C24/00
• CPC Class Codes: H05K 1/092 Dispersed materials, e.g. conductive pastes or inks
• CPC Class Codes: H05K 2203/0796 Oxidant in aqueous solution, e.g. permanganate
• CPC Class Codes: H05K 2203/107 Using laser light shaping a substrate by laser ablation H05K3/0026
• CPC Class Codes: H05K 2203/1105 Heating or thermal processing not related to soldering, firing, curing or laminating, e.g. for shaping the substrate or during finish plating
• CPC Class Codes: H05K 2203/1142 Conversion of conductive material into insulating material or into dissolvable compound
• CPC Class Codes: H05K 2203/1157 Using means for chemical reduction
• CPC Class Codes: H05K 2203/1163 Chemical reaction, e.g. heating solder by exothermic reaction oxidising metal H05K2203/0315
• CPC Class Codes: H05K 2203/121 Metallo-organic compounds
• CPC Class Codes: H05K 3/02 in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
• CPC Class Codes: H05K 3/105 by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

The present invention relates to a process for making self-patterning substrates comprising the steps of providing electrically conductive traces on a substrate; pre-coating the substrate with at least a layer of complementary reactant electrically resistant reactant formulations; altering the conductivity of complementary reactant formulation selectively upon application of external source of energy and a self-patterning substrate using the said process.

Claims

1. A process for making self-patterning substrates comprising:

providing electrically conductive traces on a substrate by;

coating the substrate at least partially with at least a layer of complementary reactant electrically resistant reactant formulation exhibiting a higher electrical resistance with respect to final conductive traces generated for a given coating surface area and thickness;

altering conductivity of the complementary reactant electrically resistant reactant formulation by applying energy from a source of energy to the layer to form the electrically conductive traces; and

triggering a redox reaction leading to a formation of the electrically conductive traces,

wherein the complementary reactant electrically resistant reactant formulation comprises at least one of precursors of metals, precursors of oxidizers oxidizing the complementary reactant electrically resistant reactant formulation, and precursors of reducers reducing the complementary reactant electrically resistant reactant formulation, and

the precursors of oxidizers or the precursors of reducers are capable of not undergoing chemical reactions under a temperature in a range from 10 to 40°

C.

2. The process for making self-patterning substrates as claimed in claim 1, wherein a single face of the substrate is coated with at least the layer of complementary reactant electrically resistant reactant formulation exhibiting the higher electrical resistance with respect to the final conductive traces generated for the given coating surface area and thickness.

3. The process for making self-patterning substrates as claimed in claim 1, wherein for the given coating surface area, an electrical resistance of a coating of the complementary reactant electrically resistant reactant formulation is higher than an electrical resistance of the electrically conductive trace being formed.

4. The process for making self-patterning substrates as claimed in claim 1, comprising coating the substrate with a plurality of layers of complementary reactant electrically resistant reactant formulations which are stacked on each other.

5. The process for making self-patterning substrates as claimed in claim 4, wherein the plurality of layers of the complementary reactant electrically resistant reactant formulations forms three-dimensional conductive trace patterns by applying heat energy from the source of energy.

6. The process for making self-patterning substrates as claimed in claim 4, wherein the plurality of layers of the complementary reactant electrically resistant reactant formulations is in solid state and/or semi-solid state and/or liquid state under the temperature in the range from 10 to 40°

C. and atmospheric pressure.

7. The process for making self-patterning substrates as claimed in claim 4, wherein in the coating of the substrate, the plurality of layers of the complementary reactant electrically resistant reactant formulations do not undergo any chemical reaction, under ambient or operational conditions, until the applying of the energy from the source of energy that changes the electrical resistance of the complementary reactant electrically resistant reactant formulations.

8. The process for making self-patterning substrates as claimed in claim 4, wherein the electrically conductive traces generate 3D conductive patterns by the applying of the energy from the source of energy.

9. The process for making self-patterning substrates as claimed in claim 1, wherein the complementary reactant electrically resistant reactant formulation comprises particles of inorganics comprising one selected from the group consisting of metals, metal oxides, metal sulfides, metal alloys, metal salts, organometals, coordination complexes, the precursors of metals, reducing agents, and the precursors of reducers.

10. The process for making self-patterning substrates as claimed in claim 1, wherein

single or multiple layers of the complementary reactant electrically resistant reactant formulation is capable of undergoing chemical transformation by the applying of the energy from the source of energy, and

the source of energy comprises at least one selected from the group consisting of a heat source, light, a resistive heat source, an inductive heat source, hot gases, an exothermic chemical heat source, a spark generator, laser, a photochemical reaction source, a mechano-chemical reaction source, a microwave, an optically-induced reaction source, and a pressure induced reaction source, to yield electrically conductive patterns of a predetermined resistance and a predetermined resolution.

11. The process for making self-patterning substrates as claimed in claim 10, further comprising heating the layers in order to change a pH of the layers of the complementary reactant electrically resistant reactant formulation(s) thereby generating electrically resistive traces or the electrically conductive traces.

12. The process for making self-patterning substrates as claimed in claim 1, wherein the electrically conductive traces include one selected from the group consisting of pure metals, mixed metals, metal alloys, metal oxides, mixed metal oxides, electrically-conductive elements, and electrically semi conductive elements.

13. The process for making self-patterning substrates as claimed in claim 1, wherein the complementary reactant electrically resistant reactant formulation comprises electrically conductive precursors which are capable of undergoing chemical reaction and producing heat, thereby forms the electrically conductive traces.

14. The process for making self-patterning substrates as claimed in claim 1, wherein the electrically conductive traces include an electrically semi conductive coating, an electrically resistive coating, and/or an electrically conductive coating.

15. The process for making self-patterning substrates as claimed in claim 14, wherein the electrically conductive traces comprise electrically semi-conducting elements selected from the group consisting of silicon, selenium, tellurium, copper, silver, aluminum nickel, gold, metal alloys, and metal oxides thereof.

16. The process for making self-patterning substrates as claimed in claim 1, wherein

the complementary reactant electrically resistant reactant formulation comprises sequestering materials, and

the complementary reactant electrically resistant reactant formulation is in a form selected from the group consisting of surface overcoats, layered compounds, clays, polymers, and porous solids.

17. The process for making self-patterning substrates as claimed in claim 1, wherein the source of energy is selected from the group consisting of a resistive heat source, an inductive heat source, hot gases, an exothermic chemical heat source, an optical heat source, laser, light, and a spark generator.

18. The process for making self-patterning substrates as claimed in claim 1, further comprising heating and cooling the substrate to promote a formation of pure metallic conductive traces with resolutions less than 20 microns thereby preventing a formation of a predetermined kind of metal oxides.

19. The process for making self-patterning substrates as claimed in claim 1, wherein the complementary reactant electrically resistant reactant formulation comprises at least one selected from the group consisting of metal salts, metal oxides, organometals, the precursors of metals, reducing agents and the precursors of reducers.

20. The process for making self-patterning substrates as claimed in claim 19, wherein the complementary reactant electrically resistant reactant formulation includes electrically conductive particles having a size of less than 100 microns and/or the precursors of metals selected from the group consisting of oxides, hydrides, hydroxides, sulfides, organ metals, metal-organics, coordination complexes involving copper, cobalt, nickel, cadmium, iron, titanium, gallium, germanium, tin, indium, platinum, palladium, aluminum, chromium, manganese, silver, zinc, and gold.

21. The process for making self-patterning substrates as claimed in claim 1, further comprising depositing conductive metals on the substrate thereby controlling resolution and resistance of the electrically conductive traces using an electroless or an electro-plating based process.

22. The process for making self-patterning substrates as claimed in claim 1, wherein the substrate comprises a material selected from the group consisting of metals, non-metals, electric conductors, electric insulators, porous materials, non-porous materials, and flexible and inflexible materials selected from the group consisting of plastic, polymers, resin, ceramic, glass, metal, metal oxides, and organic-inorganic composites.

23. The process for making self-patterning substrates as claimed in claim 1, wherein the substrate comprises a material selected from the group consisting of ceramics, composites, glass, fiberglass, laminated boards, epoxy materials impregnated with fibers, epoxy materials impregnated with fibrous materials, phenolic materials impregnated with fibers, phenolic materials impregnated with fibrous materials, carbon, silicon, silica, alumina, boria, titania, plastic, amides, imides, kapton, carbonates, esters, metal foils coated with thin inorganic electrically resistant layers of silica, alumina, zirconia, and textiles.

24. The process for making self-patterning substrates as claimed in claim 1, further comprising co-formulating the electrically conductive traces or precursors of the electrically conductive traces with reducing agents, oxidizing agents, chelating agents, binders, passive layers, or protective layers.

25. The process for making self-patterning substrates as claimed in claim 1, wherein the coating of the complementary reactant electrically resistant reactant formulation comprises particles of inorganics having a size of less than 100 microns and particles selected from the group consisting of metals, metal oxides, metal sulfides, metal alloys, metal salts, organometals, and coordination complexes.

26. The process for making self-patterning substrates as claimed in claim 1, wherein the complementary reactant electrically resistant reactant formulation is further coated with at least one selected from the group consisting of binders, crystallization inhibitors, dispersants, surfactants, humectants and defoamers.

27. The process for making self-patterning substrates as claimed in claim 26, further comprising applying the binders on the substrate before the coating of the complementary reactant electrically resistant reactant formulation, thereby binding the complementary reactant electrically resistant reactant formulation to the substrate,

wherein the binders are adhesive and cohesive binders which are capable of facilitating reaction chemistry that transforms resistive layers into conductive patterns with resolutions less than 20 microns.

28. The process for making self-patterning substrates as claimed in claim 27, wherein the binders include one selected from the group consisting of synthetic clays, natural clays, phosphates, alkoxides, inorganic polyanions, inorganic polycations, diatomaceous earth, sol-gels, aluminates, borates, silicates, titanates, zirconates, ceria, polymers, thermoset resins, and thermoplastic resins.

29. The process for making self-patterning substrates as claimed in claim 1, further comprising

depositing the complementary reactant electrically resistant reactant formulation on the substrate, and

conducting the depositing of the complementary reactant electrically resistant reactant formulation by a printing process selected from the group consisting of dip coating, inkjet printing, flexography, offset printing, gravure printing, rotary press, screen printing, pad printing, transfer printing, thermal printing, aerosol jet printing, tip dispensing, gap coating, blade coating, Meyer Bar coating, electrophotographic printing, and lithography.

30. The process for making self-patterning substrates as claimed in claim 1, wherein the electrically conductive traces are formed under an atmosphere selected from the group consisting of ambient condition, reducing condition, inert condition, and vacuum condition.

31. The process for making self-patterning substrates as claimed in claim 1, wherein the layer of the complementary reactant electrically resistant reactant formulation comprises an electrical resistance that is ten times the electrical resistance of the final conductive traces generated for the given coating surface area and thickness.