I'm almost certain that the failure mechanism for this defect is the
formation of gas bubbles during the electrolytic plating process, at the
edge of the plating resist to clearance for the pad.
The bubble prevents the complete tin plating of the exposed pad which
when etched gets through to the substrate, hence the "perfect" circle
formations that you see.
To minimize the formation of the gas, is to ensure that the plating CD
(current density) is correct for the process and area of board to be
plated, and that suitable agitation/vibration is employed to jar these
bubbles free.
Colin McVean
Production Manager
Artetch Circuits Limited
Tel: 01903 725365
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Matthew Lamkin
Sent: 05 April 2005 08:29
To: [log in to unmask]
Subject: Re: [TN] Strange marks on PTH pads...
What causes them/how are they made?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Judy Brown
Sent: Monday, April 04, 2005 11:09 PM
To: [log in to unmask]
Subject: Re: [TN] Strange marks on PTH pads...
They are commonly called mousebites. Yes I would reject them, especially
if these pads are intended to have a fillet to the component lead, for
less than minimum annular ring.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stephen Gregory
Sent: Monday, April 04, 2005 2:10 PM
To: [log in to unmask]
Subject: [TN] Strange marks on PTH pads...
Hey All!
Well, my Monday is just about to wind down...
One of my Receiving Inspectors called me back to look at some fabs we
just
got
in that had some strange looking marks on the PTH pads.
They almost look like some sort of probe marks, but I would think that
they
would
be pretty much in the same place if a fab was to have to be tested
multiple
times
for whatever reason.
You can see what I'm looking at. Go to:
http://www.stevezeva.homestead.com
and look at "Annular Ring 1-3".
The marks are on the topside of the fab only, and they are at random
places
on
the fabs.
Anybody ever seen anything like this before?
Would you accept them? If not, what would you reject them for?
Kind regards,
-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
__________________________________________________________________
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
-----------------------------------------------------
---------------------------------------------------
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
-----------------------------------------------------
|
