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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