Steven,

I do not have any profiles but I have seen many. Sidewall integrity is
related to dam height as well as to mfg. parameters, i.e., intensity of
exposure unit and developing parameters. The process latitude of these
parameters vary widely from one vendors LPI to another's. Some masks are
easy to undercut and others have tremendous process latitude. Inquire about
specific process parameters that the mask was run through. Optimum
conditions can lead to impressive sidewall integrity with the right ink.
Good luck!
-----Original Message-----
From: Joy, Stephen C <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Tuesday, June 16, 1998 11:34 AM
Subject: [TN] Solder mask profile information


>     We have been having some problems with a BGA device where we see
>     ball fatigue (solder ball cracks) after temp cycling. We think it
>     may be related to severe undercut of the solder mask.
>
>     Does anyone have information on different solder mask foot
>     profiles? How difficult is it to get a straight sidewall on
>     solder masks?
>
>     Are there any that are much better than others for this
>     attribute? What would be the trade offs?
>
>     You can contact me off line if you prefer.
>
>     Steve Joy
>     503-696-2239
>     [log in to unmask]
>
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