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Date: | Tue, 19 Dec 1995 08:54:05 -0600 (CST) |
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It sounds like etchant is getting through the via tent. It is probably
crystals that have built up or guide clips on the DES conveyors that are
piercing the resist. A thorough PM should do the trick.
Jeff Worth
IBM Austin
On Mon, 18 Dec 1995 [log in to unmask] wrote:
> We have experienced a random problem with three or four parts relative to rim
> voids.
>
> In some cases it was part of the lot and in others it was the whole lot.
>
> They have been partial, full, top and or bottom. (no consistency)
>
> They are typically one to two mils down from the surface copper and one to
> three mils in height.
>
> They are not specific to any hole size.
>
> We use Dupont APG715 Dry Film, and develop on a Atotech/Chemcut horizontal
> system using Potassium Carbonate.
>
>
>
> I would appreciate any suggestions, as to the cause.
>
>
>
>
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