Pat:

Relative to reducing the incidence of contamination on LPI masks whether
they are matte, semi glass or glossy, it has been my experience that if the
fabricator performed a double UV bump, it tended to provide a harder finish
with less porosity and therefor a cleaner surface.

Have you found this to be true.

Charlie
----- Original Message -----
From: Pat Kane <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, January 17, 2000 7:59 AM
Subject: [TN] (no subject)


> Mike
>
> Your assumptions regarding the source of your increased contamination
levels
> are correct.  The porosity, thickness, and cure of the mask has a direct
> relationship to its ability to be cleaned thoroughly.  The cleaning system
> configuration also has a role to play as to whether you are have a
> saponifier, heated DI water, and settings of the nozzle pressures.  You
are
> also correct in that matte type masks help to reduce solder balls.
>
> In any process or material change exercise it is a good idea to baseline
your
> current performance, then use this data to evaluate the effectiveness of
the
> changes implemented.  I would suggest that you test the ionic cleanliness
> levels of your existing mask finish relative to the levels of
contamination
> and effectiveness of your cleaning system.  Then repeat the experiment for
> the mask candidates you are evaluating.  There are several very good matte
> type masks on the market, so you should be able to find something to meet
> your needs.  The investigation into which mask to select requires a Design
Of
> Experiments to downselect to the best performer for your application.
>
> Contact me offline if you require further assistance.
>
> Regards,
>
> Pat Kane
> Contamination Studies Laboratories
> 765-457-8095
>
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