Ceramic capacitor cracking in South Ossetia

Why do multilayer ceramic capacitors crack?

Cracking remains the major reason of failures in multilayer ceramic capacitors (MLCCs) used in space electronics. Due to a tight quality control of space-grade components, the probability that as manufactured capacitors have cracks is relatively low, and cracking is often occurs during assembly, handling and the following testing of the systems.

Do ceramic capacitors have a crack pattern?

In the course of failure analysis it is helpful to know that most of the time not only the failed ceramic capacitor shows a crack pattern but all the surrounding cercaps as well. Well-founded knowledge of different crack patterns and failure modes also allows us to discover unsafe bending and warping lines on the PCB.

Do ceramic capacitors have flex cracks?

In every electronic assembly line where ceramic capacitors are used and printed circuit boards are depaneled the quality risk “flex cracks” is widely known. Unfortunately flex cracks in “cercaps” always extend under the metal terminations of the capacitors and electrical tests only reveal about 1% of the affected parts.

What causes a capacitor to crack?

These cracks may propagate to the top surface and will be rough or ragged with possible pieces of the capacitor burst from its bottom surface and trapped between the capacitor and board. This is a case where the solder paste has supported the capacitor ends but not the middle, allowing the unsupported component body to crack.

What happens if a ceramic capacitor falls out?

In severe cases, the body of the capacitor may even fall out, leaving just remnants of ceramic surrounded by termination and solder joints. Fortunately, improvements in ceramic technology have reduced the incidence of both types of crack, at least as far as well-made components are concerned.

What causes a ceramic capacitor to leak?

The most probably root cause is related to a potential leakage of a ceramic capacitor. This capacitor had to be replaced as a result of a non-compliance detected during manufacturing and testing phase. For the repair process, the capacitor was assembled using direct wiring soldering process.