Exposure Window
A temporal threshold defines the maximum duration that a moisture sensitive device can remain exposed to ambient factory conditions before reflow soldering. This bga floor life is governed by the rate at which the plastic encapsulation absorbs moisture from the surrounding air. If the device remains in the open air beyond this period, it becomes vulnerable to internal damage during the subsequent heat cycle.
Protective packaging must be maintained until the assembly process begins.
Moisture Absorption
Plastic packages are hygroscopic and continuously draw water molecules from their environment. Standard ratings categorise devices into specific levels of sensitivity to determine their permissible exposure duration. Higher risk levels require rapid processing or storage in dry cabinets to prevent moisture accumulation.
Safety Verification
Manufacturing facilities monitor the exposure time using tracking software or physical log sheets at each assembly stage. When the allowed duration is exceeded, the components must undergo a baking cycle to remove the absorbed moisture safely. This baking process restores the device to a dry state but can introduce solderability challenges if repeated excessively.
Process Constraint
Extreme factory humidity accelerates moisture absorption and shortens the safe exposure period. If the ambient temperature rises above standard operating conditions, the rate of water vapor diffusion into the plastic increases. Standardised testing establishes these limits under specific reference environments to maintain consistency.
