TECHNET Archives

March 2002

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:
"Marsico, James" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 13 Mar 2002 07:36:38 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (60 lines)
Earl, I looked at your pictures of missing solder balls and share your
grief.  This looks exactly what I've been seeing occasionally on our CBGAs
when removed from an assembly.  BTW, someone on Technet had referenced a
paper regarding the produciblility and reliability issues of ceramic BGAs in
a military environment, well that was authored by yours truly.  Anyway,
using BGAs at my company was a hard sell, but I did it.  The components we
use aren't off-the-shelf devices, but are custom made.  Every time there was
a component failure, it was attributed to an open BGA solder joint.  Many
BGAs were painstakingly removed (these boards are bonded to a rather large
composite restraining core) and replaced.  I think I still have sort of a
black eye for pushing the BGA technology.  Occasionally our Test Engineers
were actually able to pin-point the exact solder joint of the suspected
open.  Upon removal, low and behold the ball location of the open joint
looked exactly like your photos.  All other ball locations had remnants of
solder.  I wasn't able to do much to analyze for root cause, since, being an
OEM, the program management didn't want to spend money to research the
cause.  They were happy to just replace the components.  My theory?
Insufficient gold plating protecting the Ni barrier layer, causing the Ni to
oxidize resulting in a marginal solder ball attachment.  Nothing to
substantiate this, just a hunch.  How are you making out?  Any progress?

Jim Marsico
Senior Engineer
Production Engineering
EDO Electronics Systems Group
[log in to unmask] <mailto:[log in to unmask]>
631-595-5879


        -----Original Message-----
        From:   [log in to unmask] [SMTP:[log in to unmask]]
        Sent:   Tuesday, March 12, 2002 2:24 PM
        To:     [log in to unmask]
        Subject:        [TN] Earls pics are up, and a question...

        Hey all!

        The pictures of Earls missing balls are up! Go to:

        http://www.stevezeva.homestead.com

        ...and I have a question that's off topic here. What is a good fluid
to use in your printer stencil cleaner? We have a DEK 288 and we use no
clean paste.

        Thanks!

        -Steve Gregory-

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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
---------------------------------------------------------------------------------

ATOM RSS1 RSS2