Base-metal Electrode Multilayer Ceramic Capacitors Research Articles

Influence of BaTiO3 Sources and Dopant Levels on Annealing of BME X7R Formulations

Several dielectric compositions for high capacitance BME (Base Metal Electrode) MLCC (multilayer ceramic capacitor) applications were studied in order to correlate synthesis technique and dopant level to the effectiveness of re-oxidation condition. All formulations were based on BaTiO3 precursors which were synthesized from either a solid state or a precipitated oxalate technique. The intention of this study was to investigate the intrinsic relationship between the reoxidation conditions and the electrical properties (including HALT) of the final MLCC's and then correlate this information with synthesis technique and dopant level. The reoxidation conditions investigated in this study were temperature (800–1000°C), PO2 (7–53 PPM's) and soak time (3–9 hrs).

Characterization of copper pastes for end termination application of base metal electrode MLCCs

The steep rise in the cost of palladium metal in the last decade has necessitated significant research and development efforts for using the base metal nickel electrodes in the manufacture of multilayer ceramic capacitors (MLCCs). Copper termination paste is hence a natural choice for end termination application of MLCCs using nickel electrodes, manufactured employing the base metal electrode (BME) process. The inert nitrogen atmosphere processing of the BME MLCCs has posed many challenges in the selection of organics (vehicles, binders, and additives), copper powders, and glasses for copper termination paste development. The effect of various organics and glasses on the drying as well as fired properties of different copper termination pastes is discussed. The effect of drying temperature and drying time on the fired properties of the copper termination, and the selection criteria for right composition of glass for copper termination paste are discussed. The properties of low and high firing temperature copper termination pastes are also presented.

Highly accelerated lifetesting of base-metal-electrode ceramic chip capacitors

The ever-growing price of precious metals has promoted the widespread use of nickel and copper in the internal electrodes and end terminations of multilayer ceramic capacitors (MLCCs). While these base metal electrode (BME) capacitors are less expensive than capacitors made with palladium and silver/palladium, their unique production process produces an identifiable wear-out mechanism. Highly accelerated lifetesting is used to evaluate the reliability of BME MLCCs within reasonable timeframes by using high electric field stress and high temperature. The results of this testing are fit to a well known reliability model and then the model is used to predict device reliability under maximum rated conditions for these capacitors. Median life, t 50, is found to be in excess of 1000 years at maximum rated conditions.