Yc. Chan et al., FAILURE ANALYSIS OF MINIATURIZED MULTILAYER CERAMIC CAPACITORS IN SURFACE-MOUNT PRINTED-CIRCUIT BOARD ASSEMBLIES, Journal of materials science. Materials in electronics, 5(1), 1994, pp. 25-29
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.