Please note that the actual pictures were of 1 of the 4 defective parts.
Each part had different balls missing. One note was that the balls were
missing from the exterior row of balls on all 4 parts.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Genny Gibbard
Sent: Wednesday, March 13, 2002 9:26 AM
To: [log in to unmask]
Subject: Re: [TN] Earls pics are up, and a question...
A couple of people have commented now about the missing ball looking like it
never intended to be there in the first picture and I just have to speak up.
At first I thought it was the corner ball as well, but I looked a little
closer and about 5 rows up on the outside edge, there is clearly a pad with
no ball. I believe this is the location Earl is talking about.
Unfortunately I have no information to add to the discussion on how to deal
with this, but I wanted to make sure that the people that can interpret the
pictures get all the info out of the pictures that they can.
-----Original Message-----
From: Furrow, Robert Gordon (Bob) [mailto:[log in to unmask]]
Sent: March 13, 2002 8:01 AM
To: [log in to unmask]
Subject: Re: [TN] Earls pics are up, and a question...
Earl,
As others have stated, the 10X picture looks like there was never intended
to be a ball there. Maybe it is the lower mag and a trick of the lighting
that makes it look that way. Anyway, on the other pics it looks a lot like a
clean fracture right at the intermetallic layer. Is the underlying metal
nickel? Was the BGA fabricator using ENIG as a solderability coating prior
to the attachment of the balls? Could this be another case of "black pad"? I
know we have had instances where this has been the case. Very low level
identified, but who knows how many times the actual cause is overlooked. As
with the ENIG issue on PWB surfaces, some suppliers may be able to
completely eliminate the problem, others may have it at a low level, and the
unfortunate few may be plagued with this problem. Just some questions you
might want to check in to.
Thanks,
Robert Furrow
Printed Wiring Board Engineer
Supply Chain Networks
Lucent Technologies
978-960-3224 [log in to unmask]
-----Original Message-----
From: Earl Moon [mailto:[log in to unmask]]
Sent: Wednesday, March 13, 2002 8:31 AM
To: [log in to unmask]
Subject: Re: [TN] Earls pics are up, and a question...
Jim,
BGA's used to be my best friend, except for Arleen Weinberger and other
ladies of extreme beauty and brains. Now they are a bain, if tha's a proper
term. It's like the whole BGA world has gone to hell. Even board suppliers
are starting to suck who once had my total faith and confidence based on
constant evaluation, re-evaluation, and qualification.
At least now I have a compadre in this mess. Thanks for sharing the gief but
I'm honestly stumped but for an undying dedication to gettin this damn thing
resolved. The TI thing was bad enough but now another major supplier adds to
the MESS.
Did you give us your paper and/or its location? I'm reading all I can, OVER
AND OVER AGAIN, notwithstanding posting my brains and guts out on this site.
Hell, even Sir Werner and his cohorts can't do much. It has to be up to the
suppliers to come forth. Thought I was working concurrently with TI. Now I'm
not sure again, and haven't even begun talking with the other major supplier
with whom my last pics are associated.
Your statement about "Every time there was a component failure, it was
attributed to an open BGA solder joint" sure used to ring true but was
resolved, for a time. It seems now to be coming back.
Sorry about your, hopefully healed black eye, but should not have been the
case. However, some should suffer such a fate based on your thoughts about
how the missing ball attachment area looked compared to mine. This solder
"remnant" crap is exactly my problem and others soon to experience it. All
other surface conditions point to some process management inadequacies and
someone knows what they are and what are the failure modes/mechanisms. Just
looks like unsolderable surfaces to me and whatever happened to the IMC
layer whether too thick, too thin, or just plane way to oxidized.
My progress is limited to a very small company resource capability. The
company has spent way too much time and money doing minimal analysis. Who
the hell could afford to do more anyway. Like Sir Werner says, this crap is
just being thrown over the fence for all us ROOKIES to suck through a garden
hose. I don't do that.
I believe you're right about the nickel gold thing. What else could it be.
TI even admitted one of its suppliers was replaced to do a better job. That
hasn't been proven yet either. Maybe Friday it will when we get our first
assemblies. We'll ge to the bottom, and I do mean bottom, of this soon but
maybe not soon enough for some.
Thanks JM for some outstanding insights. Finally feels a bit, though sadly,
comforting having someone else having gone through this.
Earl
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