Metal nanoparticles and methods for producing and using same
A composition may have metal nanoparticles having a diameter of 20 nanometers or less and have a fusion temperature of less than about 220° C. A method of fabricating the metal nanoparticles may include preparing a solvent, adding a precursor with a metal to the solvent, adding a first surfactant, mixing in a reducing agent, and adding in a second surfactant to stop nanoparticle formation. Copper and/or aluminum nanoparticle compositions formed may be used for lead-free soldering of electronic components to circuit boards. A composition may include nanoparticles, which may have a copper nanocore, an amorphous aluminum shell and an organic surfactant coating. A composition may have copper or aluminum nanoparticles. About 30-50% of the copper or aluminum nanoparticles may have a diameter of 20 nanometers or less, and the remaining 70-50% of the copper or aluminum nanoparticles may have a diameter greater than 20 nanometers.
1. A method of soldering an electronic component to a circuit board, the method comprising:
applying a soldering paste comprising a nanomaterial between the electronic component and the circuit board, the nanomaterial comprising a plurality of metal nanoparticles, each metal nanoparticle being surrounded by a surfactant layer and about 30-50% of said metal nanoparticles having a diameter of 20 nanometers or less but greater than zero and the remaining 70-50% of the metal nanoparticles having a diameter greater than 20 nanometers;
heating the soldering paste until a surfactant comprising the surfactant layer melts or evaporates, thereby causing the plurality of metal nanoparticles to fuse; and
allowing the heated soldering paste to cool down to form a soldering joint between the electronic component and the circuit board.
2. The method of claim 1 , wherein heating the soldering paste comprises heating using a laser.
3. The method of claim 1 , wherein the surfactant comprises at least one amine surfactant.
4. The method of claim 1 , wherein the surfactant layer comprises two or more different surfactants.
5. The method of claim 1 , wherein the metal nanoparticles comprise copper nanoparticles.
6. The method of claim 1 , wherein the metal nanoparticles comprise a mixture of copper nanoparticles and aluminum nanoparticles.
7. A method of soldering an electronic component to a circuit board, the method comprising:
applying a soldering paste comprising a nanomaterial between the electronic component and the circuit board, the nanomaterial comprising a plurality of metal nanoparticles, each metal nanoparticle being surrounded by a surfactant layer that comprises at least one amine surfactant;
wherein the metal nanoparticles comprise a mixture of copper nanoparticles and aluminum nanoparticles;
heating the soldering paste until a surfactant comprising the surfactant layer melts or evaporates, thereby causing the plurality of metal nanoparticles to fuse; and
allowing the heated soldering paste to cool down to form a soldering joint between the electronic component and the circuit board.