I have seen this same issue before. Looking at the metal core in the middle
of the board it appears that it is solid and hence all of the pre preg flow
goes to the path of least resistance, meaning up the holes. Normally for
this type of lamination one would use pac-o-via to conform to the hole
creating a slight dimple. If this is not used then the resin will flow up to
the surface. It seems like the supplier did not do any planerization after
lamination therefore after desmear, electroless and plating a dome is
created.
Scott B. Westheimer
----- Original Message -----
From: "Stephen R Gregory" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 13, 2005 9:31 AM
Subject: Re: [TN] raised vias...
Mornin' all you Technetters!
Just to go over things once again, this
board
is a 10-layer board that has a .045" thick,
solid
copper core in the center of it. It's made
of IPC
4101/26 laminate (GF), the pre-preg is also
IPC
4101/26 (PGF).
There's 1/2-ounce copper on layers 1,5,6,
and
10, all the rest are to be 1-ounce. The
drawing
doesn't call out for ANY hole fill.
There are 163 blind vias in this board. The
drill
chart calls out for them to be .015" max.
When I first looked at the board, I
mistakenly
thought that they were just solder bumps
that
occured from the use of via-in-pad. I've
seen
these bumps before. and not thought too much
about them.
When I started worrying, was when I observed
open holes and them not being covered with
solder.
But this time, our customer fed back to us
that
the PowerPAK SO8 device (I have a drawing on
my web page of the device) was showing
insufficient
solder defects, which to me would occur if
the device
was being held above the board for some
reason...I
used a 6-mil stencil to build the boards
BTW.
We've shipped everything that we built. But
I do
have one extra bare fab that wasn't
built...that's where
the picture on my web page came from. I'm
going
have a cross section done on it...because
from the
feedback I'm getting from everyone,
something isn't
right with this fab.
Kind regards,
-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
Franklin Asbell <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
09/13/2005 07:41 AM
Please respond to TechNet E-Mail Forum
<[log in to unmask]>; Please respond to Franklin Asbell <[log in to unmask]>
To: [log in to unmask]@SMTP@Exchange
cc: (bcc: Stephen R Gregory/LABARGE)
Subject: Re: [TN] raised vias...
What was the material used for fill?
See a couple issues,
1. Excessive fill
2. No planarization
Correct via fill usually requires
planarization after fill to even the
surface, even though it appears that was not
performed at all there seems to
be an excessive amount of fill from the
start.
I would also suspect from the appearance the
presence of voids in the filled
holes. Might be worth investigating.
Franklin
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On
Behalf Of Brooks,Bill
Sent: Monday, September 12, 2005 5:54 PM
To: [log in to unmask]
Subject: [TN] raised vias...
Can someone give us a read on what they
think cause the raised vias on
Steve's website picture?
http://www.stevezeva.homestead.com page 2.
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax:
(760)597-1510
Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers
Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
-----Original Message-----
From: Steve Gregory
[mailto:[log in to unmask]]
Sent: Monday, September 12, 2005 2:28 PM
To: [log in to unmask]
Subject: Re: [DC] Raised vias
Hi Fred and Everybody!
Speaking of "Raised Vias" and "Anthills", I
have some anthills on some
Boards that we're building here now.
The anthills aren't from plugging or
anything, but are blind via in pad.
I thought that they wouldn't present too
much of a problem because I
thought that after printing paste and
reflow, everything would level
out...but that wasn't the case.
At locations where I was placing something
called a PowerPAK SO8, there
was
open solder defects at some of the joints
because (I think) of the
raised
vias. You can see the PowerPAK part drawing,
and the raised vias that
I'm
talking about on my web page at:
http://www.stevezeva.homestead.com . Go
to
"Picture Page 2" and look for "PowerPAK SO8
and Raised Vias".
I don't have a clue why the vias are raised
like that...maybe that's a
question for the TechNet.
Kind regards,
-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
---------------------------------------------------
Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16
for additional
information, or contact Keach Sasamori at
[log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach
Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information,
or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
__________________________________________________________________
This message may contain information that is
privileged and confidential to LaBarge, Inc. It is for use only by the
individual or entity named above. If you are not the intended recipient,
you may not copy, use or deliver this message to anyone. In such event, you
should destroy the message and kindly notify the sender by reply e-mail.
---------------------------------------------------
Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
