Method for making a film from silver-containing particles
Provided are silver-containing powders and a method and apparatus for manufacturing the silver-containing particles of high quality, of a small size and narrow size distribution. An aerosol is generated from liquid feed and sent to a furnace, where liquid in droplets in the aerosol is vaporized to permit formation of the desired particles, which are then collected in a particle collector. The aerosol generation involves preparation of a high quality aerosol, with a narrow droplet size distribution, with close control over droplet size and with a high droplet loading suitable for commercial applications.
1. A method for making a silver-containing film, the method comprising the steps of:
applying a layer of paste to a substrate, said paste including particles dispersed in a carrier liquid, said particles including a metallic phase with greater than about 30 weight percent silver;
removing said carrier liquid from said layer of paste and forming on said substrate a densified layer including silver from said particles;
wherein, said particles being substantially spheroidal, having a weight average size of from about 0.1 micron to about 4 microns, having a size distribution such that at least about 90 weight percent of said particles are smaller than about twice said weight average size and having a mean crystallite size of larger than about 50 nanometers.
2. The process of claim 1 , wherein:
said particles are comprised substantially of only said metallic phase.
3. The method of claim 1 , wherein:
said metallic phase comprises a first material phase and said particles further comprise a second material phase being substantially free of silver.
4. The method of claim 3 , wherein:
said first material phase comprises greater than about 50 weight percent of said particles.
5. The method of claim 3 , wherein:
said second material phase comprises less than about 30 weight percent of said particles.
6. The method of claim 3 , wherein:
said first material phase is electrically conductive and said second material phase is dielectric.
7. The method of claim 3 , wherein:
said substrate comprises a dielectric material for a capacitor and said second material phase of said particles also comprises said dielectric material.
8. The method of claim 7 , wherein:
said dielectric material is a titanate.
9. The method of claim 3 , wherein:
said second material phase comprises an oxide material.
10. The method of claim 3 , wherein:
said second material phase comprises a ceramic material.
11. The method of claim 1 , wherein:
said step of forming on said substrate a film including silver from said particles comprises heating said particles, on said substrate, to a temperature of greater than about 300° C.
12. The method of claim 1 , wherein:
said method further comprises preparing a structure of stacked layers including a plurality of first layers including a dielectric material and second layers including said particles; and
heating said structure to a temperature of greater than about 300° C. to form a microelectronic structure including a plurality of silver-containing films, having silver from said particles, and including a plurality of dielectric layers, with at least one of said dielectric layers being between two adjacent of said silver-containing films.
13. The method of claim 1 , wherein:
said particles including silver are first particles and said paste further comprises second particles compositionally different from said first particles and including palladium.
14. The method of claim 3 , wherein said second material phase is a coating substantially covering the first material phase.
15. The method of claim 1 , wherein said silver-containing film is a electromagnetic shielding film.
16. The method of claim 1 , wherein said silver-containing film is a silver metallized termination.
17. The method of claim 1 , wherein said silver-containing film is a thermally conductive film.
18. The method of claim 1 , wherein said silver-containing film is a light reflecting surface.