Amen! Lord Doug has hit it on the head.

It may interest you (academically) to know that the erstwhile company I
owned manufactured the Microcontaminometer 20 years ago, through to
1991. It was capable of measuring the ionic contamination on parts as
small as a single diode. It was not a popular instrument: I think we
probably sold less than 50 of the beasts. What we did find was that many
components were hopelessly badly contaminated. There is a whole chapter
in my book on this subject, with photos. One IC, which is shown,
measured at 12.4 µg/cm2 eq. NaCl and this is by no means exceptional.

My experience in my former professional life was that component
manufacturers cared even less about cleanliness than they did about
solderability and I know no reason why this state of affairs should be
any different today.

Brian

Cheryl Tulkoff wrote:

> I've been working on a tough but challenging contamination problem. The
> contamination causes electrical leakage fails on a precision test
> instrument. Ion chromatography analysis points to an incoming cleanliness
> problem on a SOT-23 component. Elevated choride and sulfate levels were
> found on the components (5x - 10x greater ug/in2 levels than anything
> found elsewhere on the boards). High levels were found even on our "good"
> boards.
>
> We are trying to work with our supplier to identify and fix the problem
> long term but are looking for some short term fixes as well. Repeated
> water washing of the boards (high pressure spray cleaning) improves the
> situation but does not fix it. Alcohol scrubs in the area further improve
> it but don't eliminate the problem entirely.
>
> We have a only a DI water wash process (no surfactant/saponifier
> capability).Does anyone have any board or component cleaning
> recommendations?
>
> Are there any parts makers out there willing to tell me a little more
> about parts cleaning after the lead plating process?
>
> What tool(s) do part makers use to verify cleanliness of parts?
>
> I don't have a tool capable of measuring what was found on the part so I
> don't know where to go.
>
> Thanks, Cheryl Tulkoff
>
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