Moisture Control

Our range of moisture control products are designed for the packaging of ESD and moisture sensitive devices, such as Surface Mounted Devices.

The problem with moisture

While there is no direct link between protection from ESD and protection from moisture, many devices and components require protection from both. Surface Mounted Devices (SMDs), for example, absorb moisture and then during solder re-flow operations, the rapid rise in temperature causes the moisture to expand and the delaminating of internal package interfaces, also known as “pop corning.” The result is either a circuit board assembly that will fail testing or can prematurely fail in the field.

How to create a dry ESD safe packaging system?

SCS Humidity Indicator Cards (HIC) are printed with moisture sensitive spots which change color from blue to pink, or brown to yellow, when exposed to a relative humidity level. The HIC is typically used with Desiccant inside a Moisture Barrier Bag to protect static and moisture sensitive components noting the highest relative humidity level exposure. SCS manufactures Moisture Barrier Bags with different laminates having different moisture vapor transmission rates. SCS Dri-Shield® bags are designed to be used with Desiccant and a HIC for packaging surface mount devices (SMD) trays and reels. The bags are sealed, including being vacuum sealed, containing the SMD, or other content, along with the Desiccant and selected HIC. The HIC will note the highest relative humidity exposure, so the user can determine if baking the devices is required. SCS recommends the user follow procedures defined in IPC/JEDEC J-STD-033.

In addition, a Moisture Sensitive Level (MSL) label is used to tell you how long the devices can stay outside the bag before they should be soldered onto the board. This label is applied to the outside of the bag. If the “level” box is blank, look on the barcode label nearby.