Another method is not to tent your vias. Currently we are using
a 24mil pad with 12 mil hole with 19mil opening
in the soldermask. We have not had any yield issues, even under
.050 BGAs.
Under the 1mm BGAs we use 20mil pad 10mil hole 16 mil soldermask.
"Beerman, Dennis" <[log in to unmask]>@IPC.ORG> on 06/27/2002 09:19:39
AM
Please respond to "(Designers Council Forum)" <[log in to unmask]>;
Please respond to "Beerman, Dennis" <[log in to unmask]>
Sent by: DesignerCouncil <[log in to unmask]>
To: [log in to unmask]
cc:
Subject: Re: [DC] Tented Vias?
LPI WILL slump into the hole, and your QA department may not be too happy
with the results!
We started using a via hole filler material, Peters SD2361 to fill the
vias,
with good success.
I believe we started specifying tenting and filling to avoid any
contamination that may reside in the barrel after processing and cleaning.
-----Original Message-----
From: Hybiske, Tom [mailto:[log in to unmask]]
Sent: Thursday, June 27, 2002 8:17 AM
To: [log in to unmask]
Subject: [DC] Tented Vias?
Correct me if I'm wrong members, but the term "Tented Via" was coined when
dry film solder mask was popular. The film was allowed to cover, but not
fill, the hole which both insulated it from adjacent copper features, and
in
our use, negated inspection of the via holes in general. It was good to
use
when specifying the option of plating to the point of closure, i.e.. 0.012
+.001-.012. Our inspectors would scrutinize untented vias that were
specified in this manner, and an argument usually ensued. Covering them
solved the problem. No partially filled holes. Nowadays with the use of
LPI, I guess the term "tenting" is a misnomer as the material will slump
and
possible fill the hole rather than just covering it. At a previous
employer, we first plugged the via holes with a liquid mask then covered
them with LPI. I'm presently using a 24/10 via and just mask over it with
LPI, so although while it's not tented, it accomplishes the same result.
Tom Hybiske
Bose Corporation
The Mountain
Framingham, MA 01701
> -----Original Message-----
> From: Karthik, P.V.S. (IE03x) [mailto:[log in to unmask]]
> Sent: Thursday, June 27, 2002 7:25 AM
> To: [log in to unmask]
> Subject: [DC] Tented Vias?
>
>
> Hello All,
>
> I would like to know what is a "Tented Via" and its application .
>
>
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