MSDs moisture sensitive electronic components have a limited life (Floor Life) which corresponds to the maximum acceptable time that elapses between the moment of removal from the Dry-Pack packaging up to the moment of exposure to the temperature of reflow. The IPC / JEDEC J-STD-033B.1 standard defines the standard methods for packaging, storage, shipping and use of MSDs components.
To prevent the exposure of the MSDs to environmental humidity from exceeding the Floor Life time established by the relevant MSL, it is necessary that the devices removed from the original Dry-Pack, awaiting assembly or any resealing, are stored in the environment with RH value equal to or less than 5% (“stop the clock”).
EL.C.A. is equipped with automatic warehouses “ISM ULTRA FLEX 3600” and the “ISM 500 Static” cabinet for correct management of electronic components sensitive to humidity.
The calculation of the Floor Life is done through ISM software able to establish and track the expiry date of each component with absolute precision. The software prevents the use of components whose period of exposure to humidity values greater than 5% has been exceeded. In this way the compromised components can be quickly extracted from the warehouse and taken to the baking oven.
Once the exposure limit time has been exceeded, it is necessary to restore the Floor Life by removing the moisture that has been absorbed by the component. For this purpose a drying process (bake) is used, whose modalities depend on: thickness, package size, MSL level.
It should be remembered that the high temperature bake favors the oxidation of the terminals thus compromising the weldability. The reconditioning must therefore always be considered as the last solution to be pursued.
Correct and careful management of the MSDs, in compliance with the allowed Floor Life times, with storage in the “stop the clock” phase in controlled humidity and temperature cabinets can avoid performing bake at high temperatures.