Ultra low melt metal nanoparticle composition for thick-film applications
View Patent ↗A method of forming conductive features on a substrate, the method includes reacting a metal compound with a reducing agent in the presence of a stabilizer in a reaction mixture comprising the metal compound, the reducing agent, and the stabilizer, wherein the reaction mixture is substantially free of solvent, to form a plurality of metal nanoparticles with molecules of the stabilizer on the surface of the metal nanoparticles. After isolating the plurality of metal nanoparticles, a liquid composition that includes a polymeric binder, a liquid and the plurality of metal nanoparticles with molecules of the stabilizer on the surface of the metal nanoparticles is deposited on a substrate by a liquid deposition technique to form a deposited composition. The deposited composition is then heated to form conductive features on the substrate.
1. A method of forming conductive features on a substrate, the method comprising:
reacting a metal compound with a reducing agent in the presence of a stabilizer in a reaction mixture comprising the metal compound, the reducing agent, and the stabilizer, wherein the reaction mixture is substantially free of solvent, to form a plurality of metal nanoparticles with molecules of the stabilizer on the surface of the metal nanoparticles;
isolating the plurality of metal nanoparticles with the molecules of the stabilizer on the surface of the metal nanoparticles;
preparing a liquid composition including a polymeric binder, a liquid and the plurality of metal nanoparticles with molecules of the stabilizer on the surface of the metal nanoparticles;
depositing the liquid composition on a substrate by a liquid deposition technique to form a deposited composition; and
heating the deposited composition to form conductive features on the substrate.
2. The method of claim 1 , wherein the metal compound is selected from the group consisting of metal oxide, metal nitrate, metal nitrite, metal carboxylate, metal acetate, metal carbonate, metal perchlorate, metal sulfate, metal chloride, metal bromide, metal iodide, metal trifluoroacetate, metal phosphate, metal trifluoroacetate, metal benzoate, metal lactate, metal hydrocarbysulfonate and mixtures thereof.
3. The method of claim 1 , wherein the metal nanoparticles are selected from the group consisting of silver, gold, platinum, palladium, copper, cobalt, chromium, nickel, silver-copper composite, silver-gold-copper composite, silver-gold-palladium composite and combinations thereof.
4. The method of claim 1 , wherein the metal nanoparticles are selected from a group consisting of silver, silver-copper composite, silver-gold-copper composite, silver-gold-palladium composite and combinations thereof.
5. The method of claim 1 , wherein the stabilizer is selected from the group consisting of butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, hexadecylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, diaminopentane, diaminohexane, diaminoheptane, diaminooctane, diaminononane, diaminodecane, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, methylpropylamine, ethylpropylamine, propylbutylamine, ethylbutylamine, ethylpentylamine, propylpentylamine, butylpentylamine, tributylamine and trihexylamine.
6. The method of claim 1 , wherein the reducing agent is a hydrazine compound.
7. The method of claim 6 , wherein the hydrazine compound is one or more of (1) a hydrocarbyl hydrazine represented by the following formulas: RNHNH 2 , RNHNHR' or RR′NNH 2 , wherein one nitrogen atom is mono- or di-substituted with R, and the other nitrogen atom is optionally mono- or di-substituted with R, wherein R is independently selected from a hydrogen or hydrocarbon group or mixtures thereof, wherein one or both nitrogen atoms are optionally mono- or di-substituted with R′ and wherein R′ independently selected from a group consisting of hydrogen or hydrocarbon group or mixtures thereof, (2) a hydrazide represented by the following formulas: ROC(O)NHNHR', ROC(O)NHNH 2 or ROC(O)NHNHC(O)OR), wherein one or both nitrogen atoms are substituted by an acyl group of formula RC(O), wherein each R is independently selected from a hydrogen or hydrocarbon group or mixtures thereof, wherein one or both nitrogen atoms are optionally mono- or di-substituted with R′ and wherein R′ independently selected from a group consisting of hydrogen or hydrocarbon group or mixtures thereof, and (3) a carbazate represented by the following formulas: ROC(O)NHNHR', ROC(O)NHNH 2 or ROC(O)NHNHC(O)OR, wherein one or both nitrogen atoms are substituted by an ester group of formula ROC(O), wherein R is independently selected from a group consisting of hydrogen and a linear, branched, or aryl hydrocarbon, wherein one or both nitrogen atoms are optionally mono- or di-substituted with R′ and wherein R′ is independently selected from a group consisting of hydrogen or hydrocarbon group or mixtures thereof.
8. The method of claim 1 , wherein the polymeric binder is selected from the group consisting of polyethersulfones, polyethylenes, polypropylones, polyimides, polymethylpentenes, polyphenylene sulfides, polyvinylacetate, polysiloxanes, polyacrylates, polyvinylacetals, polyamides, amino resins, phenylene oxide resins, terephthalic acid resins, phenoxy resins, epoxy resins, phenylic resins, polystyrene and acrylonitrile copolymers, polyvinyl chloride, vinyl chloride and vinyl acetate copolymers, acrylate copolymers, alkyd resins, cellulosic film, formers, poly(amideimide), styrene butadiene copolymers, vinylidene chloride-vinyl chloride copolymers, vinyl acetate-vinylidene chloride copolymers, styrene-alkyd resins, polyvinylcarbazole, and mixtures thereof.
9. The method of claim 1 , wherein the liquid is selected from the group consisting of water, n-paraffin liquids, isoparaffin liquids, cycloparaffin liquids, pentane, hexane, cyclohexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, toluene, xylene, mesitylene, trimethylbenzene, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, terpineol, tetrahydrofuran, chlorobenzene, dichlorobenzene, trichlorobenzene, nitrobenzene, cyanobenzene, acetonitrile, dichloromethane, N,N-dimethylformamide (DMF), and combinations thereof.
10. The method of claim 1 , wherein liquid deposition is selected from the group consisting of spin coating, blade coating, rod coating, dip coating, lithography or offset printing, gravure, flexography, screen printing, stencil printing, inkjet printing, and stamping.
11. The method of claim 1 , wherein the heating is accomplished at a temperature below of about 80° C. to about 140° C.
12. The method of claim 1 , wherein the metal nanoparticles comprise silver nanoparticles having an annealing temperature of about 80° C. to about 140° C., the conductive features have a thickness of more than 1 micron, and wherein the silver nanoparticles form a metal framework with a conductivity of at least about 5,000S/cm.
13. The method of claim 1 , wherein the reaction of the metal compound with the reducing agent is carried out at a temperature of from about −25° C. to about 80° C.
14. The method of claim 1 , wherein the reducing agent is a phenylhydrazine and the stabilizer comprises dodecylamine.
15. A method of forming conductive features on a substrate, the method comprising:
reacting a metal compound with a reducing agent in the presence of a stabilizer in a reaction mixture comprising the metal compound, the reducing agent, and the stabilizer, wherein the reaction mixture is substantially free of solvent, to form a plurality of metal nanoparticles during the solvent-free reduction process with molecules of the stabilizer on the surface of the metal nanoparticles;
isolating the plurality of metal nanoparticles with the molecules of the stabilizer on the surface of the metal nanoparticles;
preparing a liquid composition including a polymeric binder, a liquid and the plurality of metal nanoparticles with molecules of the stabilizer on the surface of the metal nanoparticles;
depositing the liquid composition on a substrate by a liquid deposition technique to form a deposited composition; and
heating the deposited composition to form conductive features on the substrate with a thickness of from about 1 micrometer to about 100 micrometers.
16. The method of claim 15 , wherein the heating is accomplished at a temperature of about 80° C. to about 140° C.
17. The method of claim 15 , wherein the polymeric binder has a glass transition temperature that is lower than the heating temperature for the deposited composition.
18. A method of forming conductive features on a substrate, the method comprising:
reacting a metal acetate compound with a reducing agent in the presence of an organoamine stabilizer in a reaction mixture comprising the metal acetate compound, the reducing agent, and the organoamine stabilizer, wherein the reaction mixture is free of solvent., to form a plurality of metal nanoparticles with molecules of the organoamine stabilizer on the surface of the metal nanoparticles;
isolating the plurality of metal nanoparticles with the molecules of the organoamine stabilizer on the surface of the metal nanoparticles;
preparing a liquid composition including a polymeric binder, a liquid and the plurality of metal nanoparticles with molecules of the organoamine stabilizer on the surface of the metal nanoparticles;
depositing the liquid composition on a substrate by a liquid deposition technique to form a deposited composition; and
heating the deposited composition to form conductive features on the substrate.
19. A method of forming conductive silver features on a substrate, the method comprising:
reacting silver acetate with phenylhydrazine in the presence of an organoamine stabilizer in a reaction mixture comprising the silver acetate, the phenylhydrazine, and the organoamine stabilizer, wherein the reaction mixture is free of solvent, to form a plurality of silver nanoparticles with molecules of the organoamine stabilizer on the surface of the silver nanoparticles;
isolating the plurality of silver nanoparticles with the molecules of the organoamine stabilizer on the surface of the silver nanoparticles;
preparing a liquid composition including a polymeric binder, toluene and the plurality of silver nanoparticles with molecules of the organoamine stabilizer on the surface of the silver nanoparticles;
spin-coating the liquid composition on a substrate by a liquid deposition technique to form a deposited composition; and
heating the deposited composition to form conductive silver features on the substrate.