Handle Moisture Sensitivity in PCB Board Assembly
The evolution of electronics has led to smaller footprints and higher performance, but this increased density also increases the risk for damage during assembly. One of the main causes of this damage is moisture. Moisture can cause different types of failures, depending on where it affects the circuit: it may slow down signal transmission, delay propagation, or even stop signals completely. It can also cause corrosion, which degrades the electrical properties of conductive traces and leads.
To prevent these issues, manufacturers must be aware of the effects of moisture on their products and work to reduce the risks. To do so, they must take care to handle and store the components correctly. For example, it is important to follow industry standards such as IPC-1601A for proper handling and storage of PCBs and electronic assemblies. These standards are designed to ensure that electronic devices are protected from contaminants such as moisture, and they also help to avoid electrostatic discharge (ESD) incidents.
Moisture sensitivity is especially important in pcb board assembly because it can cause problems with the quality of the finished product. It can also lead to delays in production and decreased yields. This is why it is important for PCB fabricators to know the maximum allowable moisture content (MAMC) of their materials, so they can ensure that they are following proper storage and handling practices.
Achieving these goals can be challenging because the MAMC of various materials varies. In addition, the type of PCB board can also impact its moisture sensitivity. For example, PCBs with meshed copper planes are more resistant to moisture than those without them.
How Do You Handle Moisture Sensitivity in PCB Board Assembly?
Another important factor when it comes to managing moisture sensitivity is ensuring that the right reflow temperatures are used during soldering. The temperature must be high enough to melt solder and remove excess moisture, but it should not be so hot that it causes thermal stresses that can crack or warp the board.
Finally, it is important to monitor the moisture content of a PCB throughout the manufacturing process using humidity detection techniques. These can include a dew point measurement or a capacitance measurement technique that uses hygroscopic capacitors to change their capacitance with the amount of moisture present, thereby providing quantitative moisture content data.
In the future, as PCB design and fabrication continue to evolve, it will be important to keep up with these new technologies in order to meet the needs of our customers. This will require careful handling and storage of sensitive electronic components and a thorough understanding of the impact that moisture has on them.
Moisture-sensitive devices, such as BGA and SMD packages, demand special storage and handling methods to avoid internal damage that can be difficult to detect during inspection. Following these procedures will help to improve the reliability of a finished product and reduce the need for rework or repair.
Moisture sensitive components should be stored in an antistatic bag with a desiccant pack and a moisture indicator card. The package should be vacuum sealed according to the J-STD-033 standard, which defines moisture sensitivity levels (MSL) and recommends that components be baked before use if they exceed their floor-life limit.
