Dielectric composition for forming dielectric layer for use in circuitized substrates
View Patent ↗A dielectric composition which forms a dielectric layer usable in circuitized substrates such as PCBs, chip carriers and the like. As such a layer, it includes a cured resin material and a predetermined percentage by weight of particulate fillers, thus not including continuous fibers, semi-continuous fibers or the like as part thereof.
1. A dielectric composition adapted for use in printed circuit boards and chip carriers, said dielectric composition comprising:
a cured epoxy resin material; and
a particulate filler within said cured resin material, said dielectric composition forming a substantially solid layer for use within a printed circuit board or chip carrier as a dielectric layer such that said dielectric layer does not include continuous or semi-continuous fibers as part thereof, said dielectric composition having a dielectric loss factor of from about 0.005 to about 0.028 and further including a coupling agent, said particulate filler including particles ranging from about thirty percent by volume to about forty-five percent by volume of said dielectric composition, said particles having a particle size from about five to about thirty-two microns.
2. The dielectric composition of claim 1 wherein said substantially solid layer includes a pattern of holes therein, said pattern having a density of from about 5,000 to about 10,000 holes per square inch.
3. The dielectric composition of claim 1 wherein said cured epoxy resin exhibits a high glass transition temperature (Tg).
4. The dielectric composition of claim 3 wherein said cured epoxy resin is substantially dicyandiamide free.
5. The dielectric composition of claim 1 wherein said cured epoxy resin is a reactive thermosetting resin.
6. The dielectric composition of claim 1 wherein said particulate filler is selected from the group consisting of alumina, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, beryllium oxide, boron nitride, diamond powder, titanium oxide, silica, ceramic and combinations thereof.
7. The dielectric composition of claim 6 wherein said silica is selected from the group consisting of spherical amorphous silica, hollow silica microspheres and combinations thereof.
8. The dielectric composition of claim 1 wherein said coupling agent is silane.
9. The dielectric composition of claim 1 wherein said dielectric layer has a dielectric constant within the range of from about 2.8 to about 4.0.
10. The dielectric composition of claim 1 wherein said dielectric layer has a Tg within the range of from about 165 deg. C. to about 200 deg. C.
11. The dielectric composition of claim 1 wherein said dielectric layer has a decomposition temperature within the range of from about 300 deg. C. to about 330 deg. C.
12. The dielectric composition of claim 1 further including a flexibilizer.
13. The dielectric composition of claim 1 further including a flow-control additive.