Tokio Isogai

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.