NON-DESTRUCTIVE DETECTION AND LOCALIZATION OF DEFECTS IN MULTILAYER CERAMIC CHIP CAPACITORS USING ELECTROMECHANICAL RESONANCES

摘要

High reliability multilayer ceramic chip capacitors are necessary for use in surface mounting processes which are more mechanically and thermally severe than the traditional through-hole processes. Moreover, in specific environments, even a small defect can be considered as catastrophic for the working of the electronic circuit or even of the entire system. In order to look for the failures—intrinsic latent defects and those caused by SMT soldering processes—appearing in these components, many techniques of analysis can be used. With this present work, we focus on one technique based on the principle of electromechanical resonances existing in piezoelectric materials under a d.c. bias field. The free correlation between the impedance measurement of the chip under a sufficient voltage allows us to highlight some conclusions concerning the behaviour, the nature of the defects and the long-term reliability of ceramic chip capacitors. This method has the advantage of being non-destructive, rapid, efficient and low-cost.