Patent ID: 7494557
Filing Date: 2009-02-24
Classification: B32B,C04B,H05K

Abstract:
1. A method of fabricating a monolithic, ceramic body having an internal cavity, the method comprising: a) providing first and second sheets made of a deformable dielectric material, and providing a sacrificial mandrel made of a sacrificial material that does not comprise low melting point metal or metal alloy, Woods metal, or inorganic oxide ceramic powders greater than 3 micron diameter held in a polymer binder; then b) stacking the first sheet on top of the second sheet, with the sacrificial mandrel sandwiched in-between the first and second sheets, wherein the sacrificial mandrel is not inserted into a cutout made in any of the sheets; then c) forming a laminated structure by applying sufficient external pressure to the stack of sheets to adhere the first and second sheets together, while at the same time permanently deforming at least the first sheet around the sacrificial mandrel; and then d) removing the sacrificial mandrel by heating the laminated structure to a temperature sufficient to volatilize all of the sacrificial material, thereby creating an internal cavity bounded by the first and second sheets, with no spherical balls or discs disposed inside of the cavity; and then e) further heating the laminated structure to sinter and density the laminated sheets of dielectric material into a monolithic, ceramic body; wherein the sacrificial mandrel comprises a sheet of sacrificial material with a first thick-film deposit of material deposited on a first side of the sheet of sacrificial material prior to being laminated in step c); wherein after further heating in step e) to sinter and densify the dielectric sheets into a monolithic ceramic body, the first thick-film deposit resides on a first interior surface of the internal cavity and does not touch the opposing, second interior surface of the cavity opposite from the first interior surface.