Due to improper packaging and storage of moisture-sensitive components (Moisture sensitivity level MSL for short called German moisture sensitivity threshold) Plastic-encapsulated components are not hermetically sealed, so moisture from the room climate can penetrate into the component. This moisture evaporates through rapid heating during reflow soldering. Extreme pressures arise in the component, which too Damage who. Delamination, Cracks in the component, microcracks in the DIE, tearing of bond wires etc. up to the bursting of the components (=POPKORN EFFECT) being able to lead.
Handling when the MSL is exceeded
- • Components in the drying cabinet dry at 125 ° C according to JEDEC J-STD-033
- • After drying, the components are immediately sealed in an air-permeable film / bag with moisture indicator and desiccant.
- • The MSL must not be exceeded.
- • Only open moisture-sensitive components shortly before processing.
- • Keep MSL components in the atmosphere without welding for as short as possible.
- • Always pack MSL components in an airtight film / bag with a desiccant and a moisture indicator.