Understanding PCB MSL Levels
20 January 2025
Views: 6557
In PCB manufacturing, the moisture sensitivity level of components is a key indicator of whether the PCB can be durable. We will explain its levels and why it is a key indicator with the theme of pcb msl levels.
What is MSL?
Moisture Sensitivity Level (MSL) represents the sensitivity of semiconductor components to moisture during storage and use. The higher the MSL value, the more sensitive the component is to moisture. According to the IPC/JEDEC standard J-STD-020, components are divided into different moisture sensitivity levels, which determine the treatment of components before mounting and reflow soldering.
Importance of PCB MSL
Exposure to moisture can cause IC packaging to fail, such as expansion during reflow soldering, leading to component failure. Correct understanding of pcb msl levels can prevent component damage, enhance quality control and ensure product compliance.
List of PCB MSL levels
MSL levels range from 1 to 6, where level 1 represents the lowest sensitivity to moisture and level 6 represents the highest. Here is a detailed classification of each level:
| Levels |
Storage Conditions |
Floor Life |
Handling |
Drying |
| MSL 1 |
≤ 30°C/85% RH |
Indefinite |
No special controls needed |
Pre-bagging: Optional
Desiccant: Optional
Label: If >235°C |
| MSL 2 |
≤ 30°C/60% RH |
1 year |
Requires dry pack |
Pre-bagging: Optional
Desiccant: Required
Label: Required |
| MSL 2a |
≤ 30°C/60% RH |
4 weeks |
Requires dry pack |
Pre-bagging: Required
Desiccant: Required
Label: Required |
| MSL 3 |
≤ 30°C/60% RH |
168 hours |
Requires dry pack |
| MSL 4 |
≤ 30°C/60% RH |
72 hours |
Requires dry pack |
| MSL 5 |
≤ 30°C/60% RH |
48 hours |
Requires dry pack |
| MSL 5a |
≤ 30°C/60% RH |
24 hours |
Requires dry pack |
| MSL 6 |
≤ 30°C/60% RH |
72 hours, Must be baked |
Requires dry pack and baking |
Pre-bagging: Optional
Desiccant: Optional
Label: Required |
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