Vickie Dycewicz wrote:
>
> I am looking for information on what companies are using to remove debris in
> holes before the electroless deposition (dep) process.
>
> We are getting pth voids in holes due to drill debris still in the holes after
> deburr, before dep. Cross section pictures of the pth void show a circumfrential
> void, near the center of the hole. The electroless copper leading up to the void
> is very granular, as if trying to dep over debris. I do not classify them as
> bubble voids because of the debris still left in the hole.
> I predominately see these voids in 0.022 holes, 0.261 panel thickness.
> After drill the panels are hand sanded, then through our deburr process which is
> an IS Scrubbex with 350psi high pressure spray section.
>
> I would greatly appreciate any suggestions on how to improve my process.
>
> Thanks,
> Vickie Dycewicz
> Electroless Deposition Process Engineer
> Teradyne, Inc.
> Nashua, NH
>
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Vickie:
You may clean the drill debris by washing the boards in a ultrasonic
bath. Water is fine but a mixure of water and alcohol may be better for
high aspect ratio vias specially less than 10 mils.

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