Thermal shock resistance of miniaturized multilayer ceramic capacitors

The thermal shock resistance of miniaturized multilayer ceramic capacitors (MLCs), of sizes 0402, 0603, 0805 and 1206, was investigated by comparing the leakage currents before and after thermal shock. It was generally found that smaller capacitors have a higher thermal shock resistance than larger ones. The 0402 MLC possesses a thermal shock resistance in excess of 420 C. The linear interdependence of thermal shock resistance and reciprocal of half thickness, as predicted by conventional thermal shock analysis, was not observed. Instead, the thermal shock resistance of an MLC was found to be inversely proportional to the total area of its ceramic surface. This confirms that pre-existing flaws on the ceramic surface dominate the crack initiation process and are therefore primarily responsible for determining the thermal shock resistance of an MLC.