Jon,
Sounds like you had soldermask that wasn't over bare copper. With the
SMOBC you shouldn't have that problem. With solder plated traces (some fabs
used to use that as their etch resist, I didn't know anybody was still doing
it) under soldermask you will definitely have that problem.
Regardless, if you specify SMOBC this shouldn't happen to you.
Otherwise it is exhibiting poor mask adhesion or something in your assembly
processing is out of whack.
Pattern plating is whole other fish that isn't related to finishing or
soldermask.
Sincerely,
Brad Velander
Senior PCB Designer
Northern Airborne Technology
#14 - 1925 Kirschner Road,
Kelowna, BC, V1Y 4N7.
tel (250) 763-2329 ext. 225
fax (250) 762-3374
-----Original Message-----
From: Jon Elson [mailto:[EMAIL PROTECTED]
Sent: Wednesday, January 18, 2006 11:52 AM
To: Protel EDA Discussion List
Subject: Re: [PEDA] Solder Masks for vias.
Brad Kosiance wrote:
>For a via that is close to a surface mount pad I need the solder mask to
>cover the via so that the via does not steal the solder away.
>
>Is the best way to do this to set the Solder Mask Override setting to a
>negative number (i.e. -20mil)?
>
>
Are you sure this actually works? I have seen the solder flow under the
solder mask, making the solder mask "float" over a big "bubble" of
solder. It probably makes a big difference whether the PCB technology is
SMOBC or pattern plating.
Jon
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