MLCC Failure Analysis

A multilayer ceramic capacitor (MLCC) is a small surface-mount part made of alternating ceramic dielectric and metal electrode layers. MLCCs are common in decoupling and filtering circuits, so one failed part can stop a whole board.

Ceramic is brittle. Board flexing is a common cause of cracks, for example during depanelization, handling or mounting. A difference in thermal expansion between the ceramic and the PCB adds stress during soldering and temperature cycling. Other failure modes include knit-line and thermal cracks, delamination, poor solder wetting, moisture or contamination that causes leakage current, and electrical overstress (EOS).

Our case studies in this category show these failure modes. One board had capacitors with cracks near the terminal caused by PCB flexing. Another set of parts had knit-line and thermal cracks.

For each job, the lab starts with electrical tests, including leakage current. We then use optical microscopy and cross-sectioning of the capacitor to find cracks, voids and delamination. Where needed, we use X-ray radiography and scanning electron microscopy to look deeper.

If you have failed MLCCs, request a quote and tell us about the failure and the application.