Although the LTCC technology for high frequency applications demonstrates some very advantageous features, its development is still in the early stages. The.
Low loss dielectric materials for LTCC applications: a review M. T. Sebastian1 and H. Jantunen*2 Small, light weight and multifunctional electronic components are attracting much attention because of the rapid growth of the wireless communication systems and microwave products in the consumer electronic market. The component manufacturers are thus forced to search for new advanced integration, packaging and interconnection technologies. One solution is the low temperature cofired ceramic (LTCC) technology enabling fabrication of three-dimensional ceramic modules with low dielectric loss and embedded silver electrodes. During the past 15 years, a large number of new dielectric LTCCs for high frequency applications have been developed. About 1000 papers were published and y500 patents were filed in the area of LTCC and related technologies. However, the data of these several very useful materials are scattered. The main purpose of this review is to bring the data and science of these materials together, which will be of immense help to researchers and technologists all over the world. The commercially available LTCCs, low loss glass phases and researched novel materials are listed with properties and references. Additionally, their high frequency and thermal performances are compared with the other substrate material options such as high sintering temperature ceramics and polymers, and further improvements in materials’ development required are discussed. Keywords: LTCC, Dielectric, Shrinkage, Glass, Permittivity, Q value, Temperature compensation, Constraint sintering
Introduction The microwave devices have been traditionally machined from metal, and coaxial RF connections are provided with connectors generally leading to expensive heavy and bulky packages.1,2 These metal packages cannot meet the market demand for portable and low cost modules with multiple external I/Os. Additionally, electronic circuits for the automotive industry, entertainment electronics and telecommunications have to handle today a steady increasing amount of functions occupying as tiny space as possible. In the development of complex miniaturised circuits, flexible glass ceramic tapes, so called low temperature cofired ceramic (LTCC) tapes, play a decisive role as a base material. The LTCCs have been used for the past 15 years or so, and have become crucial in the development of various modules and substrates.3–5 This technology combines many thin layers of ceramic and conductors resulting in multilayer LTCC modules and have been generally used in the form of a three-dimensional (3D) wiring circuit board today, using low permittivity (usually er
