 
| >From willli Wed Jul 23 15: |
35:46 1997 |
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Address,
I've found the recent discussions on Soldermask Residue interesting.
I've been faced with a similar problem and have investigated for
several weeks. After re-reading everyone's commments with information
I have, there are some discrepancies. Would someone elaborate on
these items. Again everyone has their method for each process, so
I'll leave names out.
Which is correct items 1 or 2?
1. Someone noted: Acid cleaners (pH 1 or micro-etchants; ph <1) would
remove some residual soldermask residues from the copper lands.
2. OTHER: Acid cleaners render soldermask residues insoluable,
in-turn "locking-in" soldermask onto the copper. Alkalines are
recommended.
My past experiences have been with item 2.
Which is correct items 3 or 4?
3. SERA testing can not detect chemical residues (i.e. soldermask
residue).
4. SERA testing will detect chemical residues off a copper land.
Please advise. Thank you.
John Gulley
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