I'm sure there's a whole pun thread hiding in there but I'll let it pass.
:^)
dw
At 02:49 PM 1/29/2003 -0500, Steve MacDonald wrote:
>Thanks to everyone for their input. I all plugged up over it.
>
>Steve
>Mass Design
>
>----- Original Message -----
>From: "Dwight Mattix" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Wednesday, January 29, 2003 13:26
>Subject: Re: [TN] Completely Plugging Vias.
>
>
> > At 08:09 AM 1/28/2003 -0800, Macko, Joe @ IEC wrote:
> > >Dwight,
> > >
> > >Great feedback. Many of our new designs are locating vias in the solder
> > >pads due to space limitations which are causing solder problems as you
>would
> > >expect.
> > >
> > >I read the PETERS tech data sheet for PP 2795-SD plugging paste. Sounds
> > >like it is formulated for plugging buried vias and does not address blind
>or
> > >through vias. What has been your experience plugging blind vias in
>solder
> > >pads?
> > >
> >
> > Works well as look as the fill is complete or nearly complete so that
> > chemistry entrappment isn't a problem. Otherwise you can get problems with
> > the final surface finish (e.g. ENIG) from process solutions being
>entrapped
> > and then leaching out to interfere with solderability (at worst) or stain
> > (at best) the final surface finish.
> >
> > dw
> >
> >
> > >joe
> > >
> > >-----Original Message-----
> > >From: Dwight Mattix [mailto:[log in to unmask]]
> > >Sent: Monday, January 27, 2003 1:58 PM
> > >To: [log in to unmask]
> > >Subject: Re: [TN] Completely Plugging Vias.
> > >
> > >
> > >At 09:47 AM 1/27/2003 -0800, Jindra, Larry wrote:
> > >
> > >
> > >
> > >Dwight, et al-
> > >
> > >We're looking at plating over conductive filled via-in-pad for 1mm pitch
> > >BGAs (small vias, thick boards). How much trouble are we going to get
>into?
> > >
> > >
> > >
> > >Keep the CTE match in mind. It's the main issue...
> > >Conductive pastes typically have a CTE around 75 ppm.
> > >Non-conductive pastes are on the order of 25ppm and therefore more
>closely
> > >matched to the FR4/Cu combination.
> > >
> > >In general, it depends on how good a job your supplier does of filling
> > >without entrapment of bubbles and curing the paste (gotta get the
>volatiles
> > >out). Most of the conductive pastes we've encountered are ~3% volatiles
>and
> > >something like peanut butter in consistency so it's a nice trick getting
>the
> > >toothpaste back in the tube without entrapped bubbles. It can be done but
> > >very ew North American fabs have the tools and a repeatable procedure for
> > >via fill (high end Asian shops have via fill nailed). You should be
> > >alright if the paste is in individual holes with individual annular
>rings.
> > >Even better if the fill is not plated over. Plating over the fill
>provides a
> > >surface for the fill to act on in the Z axis.
> > >
> > >Most of the problems we've had have been when filling tight clusters of
> > >gnd/thermal vias located all in the same pad or piece of foil; then
>plated
> > >over to make a planar, pretty finished surface.
> > >
> > >The surface plating acts like a head over a gang of expanding "pistons."
>All
> > >the Z axis force of the vias acting together sometimes lifts that pad
> > >(usually a gnd slug under some high temp IC). It's not it's an everyday
> > >occurrence but frequent enough that it's not our preferred solution.
> > >
> > >The only real advantage I see to the conductive fill is that plating
> > >adhesion has been better that for the non-conductive fills. As a result
> > >conductive fill has pretty much been relegated to the province of ATE DUT
> > >cards that need a perfect planar (filled via) surface for their delicate
> > >probes (IC test sockets). Even so our suppliers are getting to the point
> > >where plating adhesion over non-conductive fill is getting good enough
>that
> > >we'll probably get away from conductive fill all together.
> > >
> > >cheers,
> > >Dwight
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >Larry Jindra
> > >Mfg Engr Group Lead
> > >[log in to unmask]
> > >
> > >
> > >-----Original Message-----
> > >
> > >From: Dwight Mattix [ mailto:[log in to unmask]
> > ><mailto:[log in to unmask]> ]
> > >
> > >Sent: Friday, January 24, 2003 2:01 PM
> > >
> > >To: [log in to unmask]
> > >
> > >Subject: Re: [TN] Completely Plugging Vias.
> > >
> > >
> > >
> > >Consider using a 100% solids via fill material. There's several good
>ones
> > >available. Peters and Taiyo (HBI-200DB4/TA20DB4) probably have the best
>and
> > >MacuVia should be fine for this requirement as well. Stay away from
>the
> > >conductive fills if possible (CB100 et al).
> > >
> > >dw
> > >
> > >
> > >
> > >At 09:54 AM 1/24/2003 -0500, you wrote:
> > >
> > >
> > >
> > >
> > >
> > >Greeting mighty TechNetters.
> > >
> > >
> > >
> > >Here's a common question, I think, but not common enough that I found it
>in
> > >a search.
> > >
> > >
> > >
> > >Scenario-Small PWB fab shop. Customer wants vias (no larger than .016
>inch)
> > >plugged to prevent light, vacuum, you name it, from escaping through.
>Must
> > >be plugged from at least one side, and tented on the other. We build it
>on
> > >an 16x18 panel, probably .063 finished thickness with 1/1 outers. LPI
>and
> > >SMOBC ink are applied manually at this time. (squeegee, squeegee, bake
>[or
> > >tack]) We have not come up with a reliable process. New equipment is
> > >probably not an option yet, unless its like a bigger squeegee. (ha ha).
> > >
> > >
> > >
> > >Any assistance is appreciated.
> > >
> > >
> > >
> > >Steve MacDonald
> > >
> > >---------------------------------------------------
> > >
> > >Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> > >
> > >To unsubscribe, send a message to [log in to unmask] with following text in
> > >the BODY (NOT the subject field): SIGNOFF Technet
> > >
> > >To temporarily halt or (re-start) delivery of Technet send e-mail to
> > >[log in to unmask]: SET Technet NOMAIL or (MAIL)
> > >
> > >To receive ONE mailing per day of all the posts: send e-mail to
> > >[log in to unmask]: SET Technet Digest
> > >
> > >Search the archives of previous posts at:
>http://listserv.ipc.org/archives
> > ><http://listserv.ipc.org/archives>
> > >
> > >Please visit IPC web site http://www.ipc.org/html/forum.htm
> > ><http://www.ipc.org/html/forum.htm> for additional information, or
>contact
> > >Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
> > >
> > >-----------------------------------------------------
> > >
> > >
> > >---------------------------------------------------
> > >
> > >Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> > >
> > >To unsubscribe, send a message to [log in to unmask] with following text in
> > >the BODY (NOT the subject field): SIGNOFF Technet
> > >
> > >To temporarily halt or (re-start) delivery of Technet send e-mail to
> > >[log in to unmask]: SET Technet NOMAIL or (MAIL)
> > >
> > >To receive ONE mailing per day of all the posts: send e-mail to
> > >[log in to unmask]: SET Technet Digest
> > >
> > >Search the archives of previous posts at:
>http://listserv.ipc.org/archives
> > ><http://listserv.ipc.org/archives>
> > >
> > >Please visit IPC web site http://www.ipc.org/html/forum.htm
> > ><http://www.ipc.org/html/forum.htm> for additional information, or
>contact
> > >Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
> > >
> > >-----------------------------------------------------
> > >
> > >---------------------------------------------------
> > >Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> > >To unsubscribe, send a message to [log in to unmask] with following text in
> > >the BODY (NOT the subject field): SIGNOFF Technet
> > >To temporarily halt or (re-start) delivery of Technet send e-mail to
> > >[log in to unmask]: SET Technet NOMAIL or (MAIL)
> > >To receive ONE mailing per day of all the posts: send e-mail to
> > >[log in to unmask]: SET Technet Digest
> > >Search the archives of previous posts at:
>http://listserv.ipc.org/archives
> > ><http://listserv.ipc.org/archives>
> > >Please visit IPC web site http://www.ipc.org/html/forum.htm
> > ><http://www.ipc.org/html/forum.htm> for additional information, or
>contact
> > >Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
> > >-----------------------------------------------------
> > >
> > >---------------------------------------------------
> > >Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> > >To unsubscribe, send a message to [log in to unmask] with following text in
> > >the BODY (NOT the subject field): SIGNOFF Technet
> > >To temporarily halt or (re-start) delivery of Technet send e-mail to
> > >[log in to unmask]: SET Technet NOMAIL or (MAIL)
> > >To receive ONE mailing per day of all the posts: send e-mail to
> > >[log in to unmask]: SET Technet Digest
> > >Search the archives of previous posts at:
>http://listserv.ipc.org/archives
> > >Please visit IPC web site http://www.ipc.org/html/forum.htm for
>additional
> > >information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
> > >ext.5315
> > >-----------------------------------------------------
> > >
> >
> > ---------------------------------------------------
> > Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> > To unsubscribe, send a message to [log in to unmask] with following text in
> > the BODY (NOT the subject field): SIGNOFF Technet
> > To temporarily halt or (re-start) delivery of Technet send e-mail to
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
> > To receive ONE mailing per day of all the posts: send e-mail to
>[log in to unmask]: SET Technet Digest
> > Search the archives of previous posts at: http://listserv.ipc.org/archives
> > Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
>ext.5315
> > -----------------------------------------------------
>
>---------------------------------------------------
>Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
>To unsubscribe, send a message to [log in to unmask] with following text in
>the BODY (NOT the subject field): SIGNOFF Technet
>To temporarily halt or (re-start) delivery of Technet send e-mail to
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
>To receive ONE mailing per day of all the posts: send e-mail to
>[log in to unmask]: SET Technet Digest
>Search the archives of previous posts at: http://listserv.ipc.org/archives
>Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
>information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
>ext.5315
>-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------
|
