Patent ID: 7658988

Claim:
A printed circuit comprising a dielectric substrate and a plurality of discrete conductive pathways disposed thereupon; said dielectric substrate is a film or a sheet comprising a cross-linked reaction product of an aromatic epoxy and an aromatic cross-linking agent, and 20 to 60% by weight relative to the weight of said cross-linked reaction product of a particulate mixture; said particulate mixture comprising a first set of particles consisting essentially of fumed silica characterized by having an average spherical diameter from 100-150 nm, and a second set of particles wherein the second set of particles is selected from spherical silica and nano clays; said spherical silica having an average diameter from 600-700 nm and said nano clays having a shape of lamellar plates having a dimension ranging from 10,000 nm×2,000 nm×10 nm to 250 nm×250 nm×1 nm.