US Patent 7276279 - Metal microparticle sintering using metal nanoparticles

http://www.freepatentsonline.com/7276279.html

This patent from Hitachi teaches the use of metallic nanoparticles to fill the voids when sintering microparticles. Claim 1 reads:

1. A circuit board, comprising: a substrate; and a wiring conductor provided on the substrate, the wiring conductor comprising a sintered structure comprising metal particles of 0.5-10 micron average particle sizes bonded to each other through the intermediary of metal nanoparticles, and conducting metal provided in voids in the sintered structure.

US Patent 7276185 - Fused silver nanocrystal electrical conductor

http://www.freepatentsonline.com/7276185.html

Using microsized and nanosized metallic particles as fillers is known to achieve a variety of conductive polymers and adhesives. However, difficulty in handling nanoscale particles and the lack of a uniform distribution of such particles in a binding matrix have made it difficult to form conductors with nanocrystalline metals. This patent from Denso Corporation teaches a sintering process to form silver microparticles from nanocrystals to facilitate the incorporation of these materials in a matrix. Claim 1 reads:

1. A conductor composition comprising conductive particles (30a) with electrical conductivity and a solvent, wherein said conductive particles (30a) comprise crystallized Ag fillers (31) having a crystal size of 10 nm or less, and each of said crystallized Ag fillers (31) having a particle diameter of 0.1 .mu.m or more and 20 .mu.m or less.