Tony, I might think that although via plug is 'conductive' a layer of
electroless copper would greatly improve the situation. Also, some folks
will simply skip the preclean and catalyst steps and proceed to the
electroless copper bath when covering the plugs(perhaps some adverse
chemical happenings with the silver and the chlorides in the catalysts).

Here is what we are doing with good success:

Drill via
deburr/electroless copper
panel electroplate flash (20asf, 20 minutes)
CB100 vias
Electroless copper,NO PERMANGANATE DESMEAR chemistry
(we used the permanganate desmear on one job and 99% of the silver via plugs
raised up to present a 'nipple' effect on the final BGA pad. I believe the
solvent swell step softened and expanded the epoxy in the via plug
material).
panel electroplate flash (20asf, 20 minutes)
drill the balance of holes
desmear/electroless
image
pattern plate
strip/etch (depending on the construction one side may have significantly
more copper because of the 2 additional panel plates).

I hope this helps, call if you would like to talk off line.

Russell Burdick

520-745-8515



>From: tony steinke <[log in to unmask]>
>Reply-To: "TechNet E-Mail Forum." <[log in to unmask]>,   tony steinke
><[log in to unmask]>
>To: [log in to unmask]
>Subject: Re: [TN] conductive  blind via plug
>Date: Wed, 29 May 2002 13:09:50 -0700
>
>Don, Russ, Rush
>The application is a blind via under BGA pad. The process sequence is:
>Lase via
>electroless
>full panel electroplate
>CB100(lase vias only)
>flash electroplate
>drill
>electroless
>image
>pattern plate
>strip/etch
>Thanks for the input.
>Tony Steinke
>
>   ----- Original Message -----
>   From: Don Vischulis
>   To: tony steinke
>   Sent: Wednesday, May 29, 2002 9:49 AM
>   Subject: RE: [TN] conductive blind via plug
>
>
>   Tony,
>
>   Please supply process details.  The manufacturing sequence may be part
>of the root problem.
>
>   Don Vischulis
>   -----Original Message-----
>   From: TechNet [mailto:[log in to unmask]]On Behalf Of tony steinke
>   Sent: Wednesday, May 29, 2002 11:33 AM
>   To: [log in to unmask]
>   Subject: [TN] conductive blind via plug
>
>
>   Techies,
>   We have done some initial testing on the  DuPont CB100 conductive via
>plug with blind via application and so far have been unsuccessful. The
>blind via is approximately .016 diameter and .030 in depth. The biggest
>problem we are experiencing is getting adhesion(BGA pads popping off) with
>   copper plating after the CB100 has been applied. Is there
>   another type of conductive blind via plug recipe on the market.
>   Thanks for any comments
>   Tony Steinke




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