Hi Sam,

        The reason for vibrators on a plating line is rather simple, especially
for small holes and the use of electroless copper. In the electroless copper
bath, hydrogen is generated at the plating site. This sometimes causes
entrapment of the hydrogen bubble, resulting in the blinding of the plating
site within the hole. The smaller the hole the more prone to contain the bubble
within. The plating of blind vias, in the range of 6 mils and less is really
prone to this problem. Lets take a look at electrolytic plating; There can be a
similar problem here as wel. It is possible that the surface tension of the
bath may not be low enough to allow proper wetting in small holes. This means
that the Air is entraped in the hole at entry into the bath, again blinding the
plating site. The vibrators or bump technology aids in disloging the entrapped
hydrogen or air, thus allowing access to the plating site. I hope this is of
some help.

Les Connally
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>  From: sam mccorkel <[log in to unmask]>, on 11/21/97 11:16 AM:
>   What are the reasons for vibrators on a plating line?
>
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