FAILURE ANALYSIS OF MINIATURIZED MULTILAYER CERAMIC CAPACITORS IN SURFACE-MOUNT PRINTED-CIRCUIT BOARD ASSEMBLIES

New failure analysis results of miniaturized multilayer ceramic capaci tors (sizes 0402, 0603, 0805 and 1206) which have been subjected to va rious degrees of thermal shock up to 450-degrees-C by ice-water or dry ice quenching are reported. The thermal shock resistance of 0402 mult ilayer ceramic capacitors was found to be about 400-degrees-C and cons iderably better than those of the larger ones. Microstructural and lay er-by-layer insulation resistance analyses have clearly identified the physical locations responsible for the electrical leakage of defectiv e capacitors. Further, no evidence of silver migration as a dominant f ailure mechanism has been observed for any of the defective capacitors under usual operating stresses. Comparisons of I-V characteristics fo r multilayer ceramic capacitors quenched by ice-water and dry ice conf irm that water plays a significant role in causing electrical failure at nominal bias. Comparisons with results obtained from practical surf ace mount printed circuit board assembly of mobile telephones is discu ssed. From these, failure mechanisms are proposed to explain the failu re of miniaturized multilayer ceramic capacitors under normal service conditions.