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.