It is essential to keep Surface-Mount Devices (SMDs) dry from manufacturing point to the time of reflow soldering. Moisture Barrier Bag, also known as Vapor Barrier Bag, is made from multiple layers of plastic and aluminum that control moisture vapor leakage.

Basically, there are 3 kinds of Moisture Barrier Bags (MBBs)Tyvek MBB,

  • Tyvek Moisture Barrier (Tyvek MBB)
  • Aluminum Moisture Barrier Bag (AMBB)
  • Aluminized Moisture Barrier Bag (ANMBB)

The key factor of moisture barrier function of the bag is its metal layer, thickness of the foil layer, foil or metalized, but thickness or material of other layers will partially affect the quality of MBB as well.