Scott,
Why would solder be trapped in the vias?  If the board is SMOBC, with the
vias tented, there should be no problem.  But since there is, could you
provide more data on how the board is constructed?  Is it SMOBC, or is mask
applied after HASL?  What kind of solder mask is being used?  What diameter
(finished) are the vias?  Is the print specifying the board specific enough
for the finished bare board, or is it nebulous?  (How many fabricators out
there get nebulous prints?  Nobody? ;-)
One solution may be opening (un-tenting) the vias.  This may pose a problem
though with ICT.
Roger M. Stoops, C.I.D., PCB Designer


Spectra Precision Inc./Trimble Navigation Ltd.
5475 Kellenburger Rd.
Dayton, OH 45424-1099 USA
Ph: 937.233.8921 or 937.233.4574 ext 288
Fax: 937.233.7511



                    "Lefebvre,
                    Scott"                To:     [log in to unmask]
                    <Scott_Lefebvr        cc:
                    [log in to unmask]>            Subject:     [TN] Solder masked Via problems
                    Sent by:
                    TechNet
                    <[log in to unmask]
                    RG>


                    08/10/00 03:18
                    PM
                    Please respond
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                    Please respond
                    to "Lefebvre,
                    Scott"





I have a problem with via's that have been masked over having trapped
solder in the via's after HASL.  The solder that is in the via's is
surfacing after we reflow the bottom side of the board.  I have not had
this problem before and wanted some advice from all of you.  I am sending
this message again due to the lack of response I got.  Any help or advice
would be greatly appreciated!
Thank you,

Scott Lefebvre
[log in to unmask] <mailto:[log in to unmask]>

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