Microwave sintering of multilayer integrated passive devices

Microwave sintering of multilayer capacitor/varistor-based integrated passive devices (IPDs) has been investigated for the first time. The sintered samples were characterized for density, microstructure, composition, and electrical performance. It was found that IPDs with varistor/capacitor formulations could be microwave sintered to fully dense device components within 3 h of total cycle time, which is <1/10th of the time required by conventional methods. Microwave sintering resulted in products with a finer grain structure and without delamination or significant interdiffusion between the ceramic/electrode and varistor/capacitor interfaces. The microwave method also completely eliminated the need for a separate binder burnt-out step. The electrical properties of the microwave-sintered samples were found to better or match those obtained by conventional, industrial processing. In general, the simplicity, rapidity, and superior product performance make the microwave technique an attractive sintering methodology for the processing of IPDs.