MSL (Moisture Sensitivity Level) is a classification that indicates the probability that an integrated circuit or other electronic components will be damaged when they are subject to moisture. This classification is a standard defined by IPC/JEDEC J-STD-20. The MSL rating system determines the rules that must be observed during the packaging, transportation, storage and assembly processes of the components.
What are the MSL Levels?
MSL levels range from 1 to 6. MSL 1 has the lowest humidity sensitivity, while MSL 6 has the highest. MSL values are tested with moisture sensitivity devices (MSDS) offered by electronic manufacturers. They test the components at different temperature and humidity values and classify them according to IPC/JEDEC standards.
Floor Life: It refers to the maximum period of time that a component can be exposed under acceptable conditions (≤30°C/60%RH) after being taken out from the moisture barrier bag (MBB).
Moisture Barrier Bag (MBB)
How Do We Manage Moisture Sensitivity Components?
1. Correct Storage: The components should be stored with moisture barrier bags (MBB), and the humidity level should be monitored using desiccant packages and humidity indicator cards (HIC).
2. Controlled Storage Media: The temperature and levels in the storage area should be constantly controlled. Components should be stored in low humidity environments.
3. Monitoring and Recording: The storage and usage periods of the components should be checked concurrent with the floor life, and it should be ensured that these periods are not exceeded.
4. Drying Before Reflow: When necessary, a drying process should be performed before reflow soldering.
5. Proper Packaging: The PCBs that contain MSD in opened packages should be installed as quickly as possible and unused components should be sealed.
6. Training and Awareness Raising: Proper procedures and training services should be offered to the related staff about humidity sensitivity, baking temperature and baking time.
Humidity Indicator Cards (HIC)
What Conditions Do the Heat Treatment/Voltage Requirements Include for the MSL Level?
The heat treatment and voltage requirements for each MSL level have been determined in order to ensure the safe use of the components and prevent damage caused by humidity.
MSL 1:
• Soaking Conditions: 168 hours, 85°C/85% RH
• Baking Requirement: Not necessary.
MSL 2:
• Soaking Conditions: 168 hours, 85°C/60% RH
• Baking Requirement: Not necessary if the floor life has not been exceeded.
MSL 2a:
• Soaking Conditions: 120 hours, 60°C/60% RH
• Baking Requirement: Not necessary if the floor life has not been exceeded.
MSL 3:
• Soaking Conditions: 192 hours, 30°C/60% RH
• Baking Requirement: Necessary if the floor life has been exceeded.
MSL 4:
• Soaking Conditions: 96 hours, 30°C/60% RH
• Baking Requirement: Necessary if the floor life has been exceeded.
MSL 5:
• Soaking Conditions: 72 hours, 30°C/60% RH
• Baking Requirement: Necessary if the floor life has been exceeded.
MSL 5a:
• Soaking Conditions: 48 hours, 30°C/60% RH
• Baking Requirement: Necessary if the floor life has been exceeded.
MSL 6:
• Soaking Conditions: Pre-drying and 24 hours, 30°C/60% RH
• Baking Requirement: Required.
