TECHNET Archives

October 2010

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Chris Mahanna <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Chris Mahanna <[log in to unmask]>
Date:
Tue, 12 Oct 2010 23:03:15 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (353 lines)
John,
you get the prize for the first theory on this I've never (at least) heard of.
Do you have a publication reference?  On your site?
BTW, have you thought about indexing your site articles?  That would be sweet.

I like Werner's BP, but the only evidence I have so far is lack of dissolution, rather than too much.

From my first post, I believed it to be primarily a sub-par wetting problem.  Against my recommendations the customer requested 100 BGAs to be dye-n-pry.  So we know a lot about how the sub-par wetting propagates through the assembly and testing, but precious little root cause evidence (no pads found to be  black).

I think that I convinced them to test some bare boards.  I'll get you all updates.

As for FA today, from the perspective of the independent lab, very-very few are willing to spend even the bare minimum to get to root cause.  All they want to know is 1) can we ship the rest of the product, and 2) give me data for an easy CAPA.  That's why I'm always asking technet about signatures and their probability to root cause.  There is nothing worse than running out of money with no definitive root cause.

FYI, our current global failure rankings 1) cratering (not necessarily patent), 2) wetting 3) CAF 4) PB-free alloy overstress/fatigue 5) delam or cohesive laminate failure (including haloing) leading to dielectric breakdown.  All [in]directly attributable to Pb-free materials/processes.

Chris




-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of John Burke
Sent: Tuesday, October 12, 2010 6:22 PM
To: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?

Actually it is highly likely for this type of defect it to ONLY occur in the
BGA area.

This effect occurs particularly on BGA via fields using small via holes
especially in high aspect ratio boards. If the tin stripping in the outer
later etching process is not removing all tin from the through hole walls
the residual tin impacts the subsequent nickel plating process so that you
get a very thin nickel layer both in the wall and the connected pad - over
which you plate immersion gold.....giving the effect you are showing on your
photographs.

I would be inclined to take bare fabs from the same lot and do some XRF work
in those areas impacted comparing the nickel thickness to the rest of the
small component pads - I think you may be in for a surprise.


John

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Bavaro
Sent: Tuesday, October 12, 2010 10:07 AM
To: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?

Thus.....etc

I would want to inspect the rest of the board for more evidence of the black
pad, such as the smaller chip caps....for it to only occur at the perimeter
of the bga seems unlikely.  On a chip cap pad which has had solderpaste melt
and interact with the nickel underneath, the dewetting should be apparent.

Dye and Pry can be misleading as to the cause of the dye penetration,
especially when there are numerous possible mechanical questions.

Phil



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Tuesday, October 12, 2010 9:40 AM
To: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?

It sure looks like Black Pad to me.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez
Sent: Monday, October 11, 2010 2:41 PM
To: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?

Was this BGA reworked/repaired.   Is it in close proximity to another
BGA that was RW?  Did the card/board see two consecutive thermal excursions?


X"

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne - IIW
Sent: Monday, October 11, 2010 1:55 PM
To: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?

Never mind.  I just read the original post.  I'm betting the whole shebang
is due to poor wetting--that's why the correlation to the fanout escape.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne - IIW
Sent: Monday, October 11, 2010 2:52 PM
To: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?

What's going on with the picture of the cross section?  The ball isn't
wetting down the side of the plated pad.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Chris Mahanna
Sent: Monday, October 11, 2010 2:41 PM
To: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?

Here are a few pictures
http://ipc-technet.groupsite.com/gallery/16011

this job is a mixed bag.  Currently we suspect soldering, cratering, ICT and
t-cycling damage

Chris

From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Monday, October 11, 2010 2:22 PM
To: TechNet E-Mail Forum; Chris Mahanna
Cc: [log in to unmask]
Subject: Re: [TN] Mech. damage or poor wetting?


Hi Chris - do you have any pictures you can share?

Dave Hillman
Rockwell Collins
[log in to unmask]

Chris Mahanna <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>

10/11/2010 11:29 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to Chris Mahanna
<[log in to unmask]>


To

[log in to unmask]

cc

Subject

[TN] Mech. damage or poor wetting?







We have a BGA dye-n-pry job that shows board side sj damage with a strong
correlation to fan-out clocking.
We also have some microsection evidence of poor wetting.
All damage/dye is on perimeters.

Is this an indication of heat sinking and subpar wetting, or can it be
completely mechanical?  Both?

Thanks

Chris

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 e-mail and any files transmitted with it may be proprietary and are
intended solely for the use of the individual or entity to whom they are
addressed. If you have received this e-mail in error please notify the
sender.
Please note that any views or opinions presented in this e-mail are solely
those of the author and do not necessarily represent those of ITT
Corporation. The recipient should check this e-mail and any attachments for
the presence of viruses. ITT accepts no liability for any damage caused by
any virus transmitted by this e-mail.

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------

ATOM RSS1 RSS2