Decreasing the relative permittivity of LTCC by porosification with poly(methyl methacrylate) microspheres

Low Temperature Co-fired Ceramic (LTCC) is one of the cornerstones of today׳s multilayer electronics. However, the relatively high permittivity of LTCC materials limits their usage at high frequencies. In order to expand the applications of LTCC a method to decrease the permittivity is needed. In this paper, commercially available LTCC materials have been de-binded into powder, mixed with slurry additives and poly(methyl methacrylate) microspheres, tape cast, laminated and co-fired to form a porous ceramic. Relative permittivity, and dielectric losses of the samples were measured in the frequency range from 2.47 GHz to 9.97 GHz. The lowest εr was achieved for the sample with 33 vol% porosity; this permittivity was 32% lower compared to reference value with no observable effect on the losses. The microstructure of the samples was analyzed with FESEM. The proposed method clearly proves to be a promising way for to manufacture LTCC compositions with low εr.