Abstract: A sealed composite ceramic structure is formed by first forming a plurality of composite green sheets. Each of the green sheets is a composite structure comprising a central portion of partially densifiable material and an outer portion of fully densifiable material. Next, top and bottom green sheets of fully densifiable material are formed. The greensheets are then stacked to form a laminated structure in the following order: the bottom green sheet, the plurality of composite green sheets, and the top green sheet. The substrate laminate is sintered to form the sealed structure having a porous central portion. The composite structure has particular application to ceramic substrates for mounting semiconductor devices requiring low dielectric constant substrates, but the structure also has applications in fluid processing using porous laminated structures. In both applications, the creation of a porous ceramic body with solid, sealed edges and/or external surfaces hold significant advantages.

Abstract: A large ceramic substrate article for electronic applications including at least one layer of sintered ceramic material, the layer including a plurality of greensheet segments of ceramic material joined edge to edge. Also disclosed is a method of fabricating a large ceramic greensheet article as well as a large ceramic substrate article.