Processing and electrical characterization of co-sintered composite glass ceramics

The demand for smaller size with increased functionality in electronic devices require new materials, which will allow integration of passives elements in substrate. Low temperature co-fired ceramic (LTCC) is a glass ceramic substrate technology that offers an excellent platform for multi-functional integration. This paper describes manufacturing challenges in co-sintering of composite dielectric materials in multi-layer configurations and the extraction of high-frequency electrical characteristics of fabricated embedded capacitors. Processing of LTCC composite materials with mixed dielectric properties required modified fabrication processes. A combination of the controlled printing process and the split-step lamination produced excellent planarity which rendered the substrate suitable for post firing processes such as flip chip or other components assembly. The extracted effective capacitance for electrode area of 2.3 times 2.3 mm ² capacitors for high dielectric layer is approximately 15 times of that obtained from the normal tape. This is due to the high permittivity layer. With the integration of high permittivity tape, the capacitance is significantly higher than that of the normal tape. It was also observed that the self-resonant frequency is well beyond 1 GHz, even for the high permittivity tape integration