Jeff and Roger - You've both proposed these vias be filled with conductive
via fill.  But the fill does not need to be conductive.  We've used both
types of fill materials and found the non-conductive to have superior
processing capability.

Mike McMaster
RF Product Engineer
Merix Corporation
503-992-4263



> ----------
> From:         Jeffrey Bush[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Jeffrey Bush
> Sent:         Friday, June 25, 2004 9:20 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] VIA in Pad
>
> I will suggest a conductive via fill in these areas to provide a flat
> SMT site, because - solder joint could be starved by flow down into the
> via.  Also Sm plugged on the opposite side will also cause excessive
> voiding as the capped via will provide a good outgassing effect during
> relow.  Not the cheapest solution but is effective in hiding vias in
> pad.
>
>
>
> Jeffrey Bush
> Director, Quality Assurance and Technical Support
>
>                           76 Technology Drive - POB 1890
>                              Brattleboro, Vermont 05302-1890
>                                 Tel. 802.257.4571.21 Fax. 802.257.0011
>                                     [log in to unmask]
>                               http://www.vtcircuits.com
>
>
>
> -----Original Message-----
> From: Tom Parkinson [mailto:[log in to unmask]]
> Sent: Friday, June 25, 2004 11:14 AM
> To: [log in to unmask]
> Subject: [TN] VIA in Pad
>
>
> We're a CM.  One of our customers is asking us to build a board assembly
> that will be using BGAs with VIAs in pads.  They are in the design
> stages at this point, and we have some concerns with having a Via in the
> middle of a BGA pad.  Anyone have suggestions and/or experience with
> this??
>
> Thanks
>
>
> Tom Parkinson - Quality System Manager - CIT
> WinTronics, Inc.
> Ph: 724-981-5770 Ext. 235
> Fax: 724-981-1772
>
>
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