Capacitive devices, organic dielectric laminates, and printed wiring boards incorporating such devices, and methods of making thereof
View Patent ↗A polymeric dielectric composition is disclosed, having a paraelectric filler with a dielectric constant between 50 and 150. Such compositions are well suited for electronic circuitry, such as, multilayer printed circuits, flexible circuits, semiconductor packaging and buried film capacitors.
1. A capacitor consisting essentially of a dielectric composition comprising a paraelectric filler and a polymeric material said dielectric composition disposed between two conductive electrodes;
wherein said filler has a dielectric constant between 50 and 150;
wherein said paraelectric filler is selected from the group consisting of Ta 2 O 5 , Hf 2 O 5 , Nb 2 O 5 , Steatite and mixtures thereof, and
wherein said paraelectric filler is present in an amount of 5 to 55 volume percent.
2. The capacitor of claim 1 wherein the average particle size of said paraelectric filler is less than 2 microns.
3. The capacitor of claim 1 wherein said polymer is selected from an epoxy, acrylic, polyurethane and polyimide.
4. The capacitor of claim 1 further comprising a ferroelectric filler.
5. The capacitor of claim 4 wherein said ferroelectric filler is selected from the group consisting of perovskites of the general formula ABO 3 , crystalline barium titanate (BT), barium strontium titanate (BST), lead zirconate titanate (PZT), lead lanthanum titanate, lead lanthanum zirconate titanate (PLZT), lead magnesium niobate (PMN), calcium copper titanate and mixtures thereof.
6. The capacitor of claim 1 wherein said composition has been processed to form a film.
7. A method of forming an embedded planar capacitor comprising:
providing the dielectric composition of claim 1 ; applying said dielectric composition of claim 1 to a first metallic layer, thus forming a metallic side and a dielectric side; and applying a second metallic layer to said dielectric side.
8. An embedded planar capacitor formed by the method of claim 7 .
9. A printed wiring board comprising the capacitor of claim 1 .