BGA Moisture Sensitivity Level Qualification and Inspection Standard
BGA moisture sensitivity compliance demands strict floor life tracking, J-STD-020 preconditioning qualification, and acoustic inspection for subsurface delamination.
Pre-Bake Cycle
Moisture Removal
Preventing the destructive expansion of absorbed water within plastic component packages during high-temperature reflow requires a controlled drying process prior to assembly. This preparation is the pre-bake cycle, a long thermal exposure at a moderate temperature designed to drive out moisture without causing thermal damage or oxidizing the solderable leads. The process is typically conducted in specialized baking ovens where the temperature is maintained between ninety and one hundred and twenty degrees Celsius.
It is applied to moisture-sensitive devices that have exceeded their allowed floor exposure limit.
Parameter Control
The duration of the cycle varies from several hours to days, depending on the moisture sensitivity level of the device and the thickness of the package. Low-temperature bakes at forty degrees Celsius are sometimes used when the components are stored in their original trays to prevent the tray material from melting or warping. This slower process requires a low-humidity environment to ensure moisture is drawn out effectively over the longer duration.
Operators must log the start and end times to confirm the cycle has been completed successfully before release to assembly.
Oxidation Prevention
Extended exposure to heat can accelerate the oxidation of component terminations, which diminishes their solderability.