Ingemar,
If you forward images to us we'll give you Lucent's "two cents".

Regards,

George
George M. Wenger DMTS
Bell Laboratories Princeton, Supply Network Solutions
Engineering Research Center FMA / AQA / RCA Lab
(609) 639-2769 (Office); 3210 (Lab); 2343 (Fax)
[log in to unmask]


-----Original Message-----
From: Werner Engelmaier [mailto:[log in to unmask]]
Sent: Friday, January 26, 2001 4:22 PM
To: [log in to unmask]
Subject: Re: [TN] Ni/Au solderabilty


Hi Ingemar,
I send an e-mail as soon as you send me the pictures.
Here it is again:
Wow Ingemar,
My favorite 'Katarina' is Ms. Witt of East-German skating fame--now there is
a woman.
Back to SJs. Well I eat my hat--however, not to waffle about it, if this is
really Ni, this solder joint must have been liquid for a loooong
time--certainly not standard reflow. Any abnormal temperature history you
are
aware of?
Whatever it is, to be that brittle and weak to have BGAs fall of the PWBs
reminds me of the industry experience in 1982 when the TI Ag-plated PLCCs
fell of the PCBs at IBM; Ag/Sn IMCs are very weak.
I hope my Qs below may get you thinking in some helpful directions--I
wouldn't expect too much help from the PWB and BGA makers, however.
Q1. How come the Ni plating is recessed below the Cu pad surface rather than
be on top (Photo 1)?
Q2. How sure are you this is really Ni?
Q3. I take it the Ni was Au-plated; where are the Au-IMCs?
Q4. In Photo 2, why is the conclusion: "indicationg unsatisfactory joining
con
ditions?
Q5. In Photo 2, which is the same SJ as Photo 1, it is stated that  this pad
is solder mask defined; in Photo 1 there is no indication of the the typical
SMD-solder ball geometry--it sure looks much more like NSMD.
Werner Engelmaier

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