The main factors contributing to cracking Multilayer Ceramic Capacitors (MLCC) are the brittleness of the ceramic materials and the thermal and mechanical stresses associated to SMT assembly processes.
During manual rework, one of the main risks for these MLCC is the thermal shock that takes place when the soldering tip touches directly the component. When this happens, all the heat on the tip is transferred without control to the capacitor creating cracks on it.
In order to mitigate damage to MLCCs, manufacturers have been providing guidelines to reduce the risk of cracking like applying the soldering tip only to the pad so the heat is transferred to lead through the solder alloy, preheating the chip to more than 150°C to reduce the temperature gradient that takes place as soon as the soldering tip is applied, etc.
