Pop Corn Effect

Many electronic components are susceptible to damage due to moisture and have to be stored in such ways that they are protected from moisture in the environment. If they are stored in normal atmosphere, the components could absorb moisture. When these components then pass through the reflow system, the fast rise in temperature will cause the absorbed water to vaporize, building up immense pressures within the package. The formation of cracks or even the package popping can be the result. This bursting open of the package is designated as the popcorn effect. The maximum storage time in normal atmosphere is given by the MSL (Moisture sensitivity level), which normally is provided as part of the component label or on the datasheet.