Yasutaka Sugimoto

Development of a Novel Low Temperature Co-Fired Ceramics System Composed of Two Different Co-Firable Low Temperature Co-Fired Ceramics Materials

Two co-firable low temperature co-fired ceramics (LTCC) materials with different permittivities were investigated. The first material has low-K and high stiffness, and the second material has high-K, high-Q, and near zero temperature coefficient of capacitance (TCC). A resistor material, which is mainly composed of RuO2 and glass, is able to be buried into the LTCC substrate. To adjust the properties to the electric circuits, laser trimming of the embedded capacitors and resistors was performed. The constrained sintering method was applied to the substrate, and the dimension accuracy of the substrate is excellent.

Novel Low Temperature Co-Fired Ceramic Material System Composed of Dielectrics with Different Dielectric Constants

We found that the co-firing low temperature co-fired ceramic (LTCC) materials of different dielectric constants (er) with Cu wiring is achievable using a novel, original design. It was confirmed that the dielectric characteristics of the dielectrics designed in this study are very suitable for the use of the dielectrics in electronic components such as filters mounted in high-speed radio communication equipment. The dielectric constants of the lower- and higher-dielectric-coefficient materials were 8.1 and 44.5, respectively, which are sufficiently effective for downsizing LTCC components. Observing the co-fired interface, it was confirmed that excellent co-firing conditions resulted in no mechanical defects such as delamination or cracks. On the basis of the results of wavelength dispersive X-ray spectrometry (WDX) and X-ray diffractometry (XRD), it was confirmed that co-firing with minimal interdiffusion was realized using the same glass for both dielectrics. It is concluded that the materials developed are good for co-firing in terms of the mechanical defects and interdiffusion that appear in them.

Novel Glass-free LTCC Material co-fired with Cupper-Electrodes

Abstract Low Temperature Co-fired Ceramics (LTCC) have excellent high-frequency characteristics and have widely been used for microwave electronic components. By lowering the sintering temperature of the ceramics used as insulating layers, LTCC was co-fired with a high-conductivity wiring conductor, such as Cu or Ag. LTCC substrate has been expected as one of the most promising technologies to realize miniaturization of RF circuits in the field of wireless communications. There is no limitation to demand for further downsizing of RF circuits, suppression of electric loss and high mechanical strength of the substrate. However, conventional LTCC materials for substrates contain glass frit which causes defects, such as pores or cracks, and low mechanical strength. In this work, we have developed a novel LTCC material system BaO-Al2O3-SiO2-MnO-TiO2, without any glass frits. The material was co-fired with cupper electrodes, which have low resistivity and show less diffusion than silver in LTCC, under a low-oxy...