Nobuyuki Sugishita

Development of the Thick - Film Capacitor and Its Application for Hybrid Circuit Modules

New dielectric pastes with high and low dielectric constants and an advanced passivation system have been developed for highly reliable capacitors and crossovers in thick-film circuit modules. Colloidal magnetite has been found to be a good sintering agent in BaTiO 3 -based high-K dielectric paste, and a crystallized low-K glass paste has been found to be suitable for small capacitors and crossovers. Alloyed Ag/Pd and Ag/PdO have been developed for conducting electrodes, which are compatible with the dielectric materials and the firing process. Physical defects are the critical factors in the glass passivation systems for the reliability because of possible moisture diffusion into the dielectrics. A new two-layered passivation system has been adopted. The capacitor system has been applied to an RF/IF thick-film hybrid module for radio-cassette recorders.

PROCESSING CONSIDERATIONS OF THICK FILM DEVICES WITH MULTILAYERED RESISTORS

The results of a study into the fabrication of thick film multilayer devices which include resistors on and under the thick film dielectric layers are presented. Although the resistive values of the resistors under the dielectric change in the succeeding firing processes are influenced by the geometry of the resistors, the ratio of the resistivity change in resistors fabricated with the same sheet resistivity pastes and the same geometry is almost the same. The TCR of the resistors under dielectric layers is influenced mainly by the multi-firing processes. The resistive values and TCR of the resistors on dielectric layers are relatively uninfluenced by the dielectric. The stability of these resistors including trimmed ones under long-term thermal storage at 150℃ is compared with that of resistors on alumina substrates.