Moisture Restoration
Sorption of moisture by plastic-encapsulated microcircuits during assembly requires controlled exposure times to prevent damage during reflow. A floor life reset defines the procedure of baking or storing components to restore their allowed exposure duration before assembly. This action ensures that moisture levels within the package remain below the critical threshold required to avoid internal delamination.
Bake Protocol
Restoration of floor life typically involves exposing the sensitive components to elevated temperatures in a dry bake oven for a duration determined by the component’s moisture sensitivity level. Alternatively, storing the parts in dry cabinets with very low relative humidity can stop or slowly reverse moisture absorption depending on the time of exposure. The baking process must be carefully controlled because excessive bake cycles can degrade the solderability of component leads or cause intermetallic growth.
Following the prescribed thermal profile resets the floor life clock, allowing the parts to return to the active assembly floor safely.
Process Integrity
Uncontrolled moisture exposure results in board defects when the components are heated during reflow. Implementing a floor life reset is necessary to recover valuable parts that have exceeded their allowable exposure limit. This reset protects assembly yields from moisture-related failures.
