ACOUSTIC MICROSCOPY OF TIGHTLY CLOSED DELAMINATIONS IN MULTILAYER CERAMIC CHIP CAPACITORS

摘要

Acoustic microscopy is a well-established technique to nondestructivcly evaluate multilayer ceramic chip capacitors (MLCCs) for flaws such as delaminations. cracks and voids. Results of destructive physical analyses (DPA) by cross- sectioning correlate well with results of the nondestructive evaluation in most cases. However, if the delaminations are tightly closed, optical and scanning electron microscopy of the sectioned samples may be inconclusive. An acoustic micro imaging technique, Rayleigh wave imaging, which is performed on the surface of the physically sectioned sample, is introduced in this paper. This technique is sensitive to delamination defects (even if they are lightly closed) and other flaws close to the surface of the sectioned sample and is ideally suited for verification of conventional acoustic micro imaging data