Patent ID: 7067026

Claim:
A low-temperature co-fired ceramic structure consisting essentially of an upper portion and a lower portion, wherein each portion comprises an assembly of one or more layers of glass-containing primary tape and one or more layers of low k or high k glass-containing internal self-constraining tape, and wherein the self-constraining tape and primary tape is arrayed in combinations to provide symmetric and/or asymmetric z-axis placement and layer thickness arrangements to form co-fired ceramic circuit structures when the tapes are metallized with planar interconnecting circuits wherein the dielectric constant of the low k self contraining tape is less than 8, the dielectric constant of the high k tape is greater than 8, wherein each portion has z-axis symmetry with respect to the tape layers of the portion, wherein the structure, consisting of the upper and lower portions, has z-axis asymmetry with respect to the dielectric constant of the self constraining tape layers, and wherein each self-constraining tape can independently provide a self-constraining pressure-less assisted sintering LTCC assembly with the primary tape and wherein, upon thermal processing, the glass of the self-constraining tapes initiates sintering to attain a rigid form before the onset of sintering of the primary tape, and wherein the internal self-constraining tapes and the primary tape are laminated to form a compositionally asymmetrical laminate and wherein the assembly is thermally processed producing a structure exhibiting an interactive suppression of x,y shrinkage.