It's not possible! But it happens....
Small RF transistors with gullwings and a 2mm circular ceramic body. And
 a metal cover that is molded on to protect the inside where the chip
and the bonding is (not the real hermetic version, with other
words).When these tiny creatures are machine soldered on the boards
something rare happens. The first sign after soldering is that the
amplifier gain goes down. OK. What seems to happen is the following.
When at soldering temperature (approx. 220 Celcius), the molding
softens, the cap is slighly lifted, the bubbling flux goes in and drops
on the chip. The temperature decreases,  the molding hardens again, and
behold, we have a transistor with built-in flux.

I'm a skeptic but my surroundings think this is what happens. If someone
out there says 'oh, hello, just what we have all the days' so please
tell me how you tell the semiconductor manufacturer, I dare not yet!

                                 Regards // Ingemar EMW

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