Hi Sue -

The information you have provided is very sketchy.  By description, I would
be suspicious of several things: First, the possibility of some form of
process residues remaining in the junction between circuits and board
surface; Second, some variance in the cured state of the solder mask.

I would be very reluctant to accept these boards, without a clear
understanding of the origin of the visible conditions, and some form of
definitive proof that they will withstand their intended use environments.
The discolorations and pinholes may be conditions which can promote early
failure or they may be totally benign, dependent on your findings.

This is an item you need to work with your board assembler, their
fabricator, and possibly even with the assistance of the solder mask
formulator.  There is considerable variation in masks, by type of materials,
and by their application processes.  This makes it rather difficult for any
of us to give you a clear answer without further information.

If I may be of assistance, please contact me.

Regards - Kelly

-----Original Message-----
From: Sue Hedrick <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Thursday, January 06, 2000 2:19 PM
Subject: [TN] Solder mask question


>Hello, everyone,
>
>Our incoming inspection has received some assembled boards for evaluation.
>The solder mask on these boards is darker along the edges of the traces.
>There are pinholes in the darkened solder mask and at certain angles there
>are lighter spots. The mask adheres when scraped with the end of a tweezers
>although I have not done a tape test. This condition affects 3 out of 8
>boards.
>
>Could someone enlighten me as to what this is and whether it presents a
>problem?
>
>Thanks,
>Sue Hedrick
>
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