If it really is debris, people have approached it over the years with high
pressure rinse modules after drill and when we had a shop we used a vapor
hone  followed by a high pressure rinse module to clean the hole.  Be aware
our experience was that vapor hones tend to eat themselves up and require
continuous maintenance.  If it is a ring void them you have a different
problem and that is probably drilling parameter related or material degree
of cure.  Are you peck drilling?

> -----Original Message-----
> From: Vickie Dycewicz [SMTP:[log in to unmask]]
> Sent: Tuesday, February 02, 1999 10:03 AM
> To:   [log in to unmask]
> Subject:      [TN] Removing Debris from Holes before Electroless
> Deposition
>
> 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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