Kathy,

MIMICs have operating frequencies which can exceed 100 GHz. At these
frequencies
any variations in the condition of the conductive surfaces (skin effect)
will cause widely divergent result in the operation. The contents,
dispersal pattern , and concentrations of
the "no-clean" flux are not controllable. Thus you will have issues with
impedance changes and dissipation factors among others.

If the unit was not completely dry when sealed then you will also have
moisture related issues.

Please keep in mind that "no-clean" is a title and not a spec. It does
have limitations, which if ignored, can be quite costly.

David A. Douthit
Manager
LoCan LLC

"Stillings, Kathy" wrote:

>
> A question for the experts...
>
> Is anyone using no-clean on hermetically sealed units?  I am running
> into an issue with flux contamination on a few solder joints in a unit
> that contains MIMICs and wedge bonds and is hermetically sealed.  The
> flux comes from a couple of magnet wire terminations in the unit.  Can
> anyone share some insight?