I've had that experience due to moisture in the pcb. As it went over the
wave it outgassed through vias and plated through hole ( cracking the
walls). We cleared it up initially by baking the boards then addressed the
problem with our bare board vendor.
Jim Gleason
-----Original Message-----
From: annie laberge <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Wednesday, January 06, 1999 8:55 AM
Subject: [TN] pinholes


>Good morning everyone
>
>On some of our products, we have pinholes in Through holes solder joints.
>We have no idea what is the root cause of these pinholes.
>Could the root cause come from the PCB ? And if so, what default in the PCB
>could cause this ?
>
>These products are 8 layers PCB, with 4 ground planes which 2 of them are
>on outer layers, and 0.093" thick, and the hole diameter is 0.023".
>
>With these products, we had lots of problems.
>Fist we had missing solder because of the lack of heat caused by the heat
>disssipation of the ground planes.
>We optimised our wave parameters to minimize the problem.
>Then we had blow holes.   The root cause was humidity in the board.  We
>don't have this problem anymore.
>
>Any help would be greatly appreciated, thanks in advance.
>
>A. Laberge
>Quality Eng.
>Matrox
>
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