Component Process Change Notice Technical Data Baseline Qualification Requirements
Process change notices demand technical baseline audits, J-STD-046 notifications, and JESD47 qualification data to clear component changes without recall risk.
MSL Reclassification
Meaning
Component handling protocols establish the allowable exposure time for moisture-sensitive devices before board-level reflow soldering. The process of msl reclassification adjusts this time limit when packaging styles or manufacturing conditions deviate from the original factory ratings. It ensures that plastic-encapsulated microchips do not suffer from internal cracking during high-temperature oven cycles.
Moisture Absorption
Plastic packages absorb humidity from the surrounding air over time. During the rapid heating of reflow soldering, trapped moisture expands into steam, creating internal pressure that can delaminate the silicon die from the lead frame. This phenomenon can destroy a component without showing visible damage on the outer casing.
Technical Evaluation
Test standards from joint electron device engineering councils define the specific humidity levels and durations used to classify devices. If a supplier changes the mold compound or the die-attach material, the product must undergo re-evaluation to determine if its sensitivity rating has changed. This testing involves preconditioning the parts in humid chambers before exposing them to peak reflow temperatures to check for internal structural damage.
Acoustic microscopy checks the interface layer for microscopic voids that indicate separation after the thermal shock. Such verification ensures that modified parts do not introduce hidden defects into the final assembly.
Reclassification Process
Changing a device sensitivity level from a strict class to a more lenient one requires extensive validation data. Manufacturers bake the components to remove moisture and then store them in sealed moisture barrier bags with fresh desiccant cards. The updated classification level is printed on the barcode label to guide the assembly floor operators regarding the allowable out-of-bag floor life.