We frequently receive inquiries about the moisture sensitivity of our surface mount components.Technically, all of our components are moisture sensitivity level 1 (MSL1) according to the IPC/JEDEC’s J-STD-20, meaning that they can be mounted and reflowed an unlimited amount of time after they are removed from the packaging. This is not the complete story however.
Because of the unique, high frequency construction of our surface mount devices, the lid provided for them is only a dust cover, epoxied on. For this reason it is not sealed against aqueous solutions, and special precautions need to be made.
All sensitive elements inside of the units are sealed independently, and the circuits themselves are not moisture sensitive. However, during the aqueous wash process the solution will penetrate the components and therefore will require some time to dry.
For this reason, Marki Microwave suggests that all surface mount components be subject to a vacuum bake at less than 120° C for one hour.
The important element in this is the vacuum, which will cause the solution inside to evaporate and evacuate the dust cover. A lower temperature or lower vacuum can be used, but it must be subject to the process for a longer time. If the part is tested within 24 hours after an aqueous wash, then the performance will be affected by the solution still inside the dust cover.