Hard to see what is what, but first I would handsolder pads, copperwick and solder again, just to see if there is a very severe situation. Rough but direct. Then I would look at the dewetted areas in SEM to find what is left, total dewetting or partial, again, tells a little about trouble level. After that I would look hard on real dewetted areas to see what is left: oxidized Nickel? Porous Nickel? Too high P content Nickel? Copper infiltrated Nickel? Maybe no Nickel at all? Etc according to classical fishbone analysis tree. Following will be having a look at the test coupon, make wetting test to see if the supplier has a fundamental process problem, prefer putting large number of Sn60 balls together with flux on a large number of pads, put through oven an check wetting diameter of each, gives an idea about over-all-area-yield. If you didn't get the key then, you have to go one with analysis of cross section, look for composition of respective layer, look for Oxygene peaks..!
.dollars will flow rapidly when you end up with TOFSIMS, ESCA or whatever advanced methods for characterizing the layers. People solve this problems different, but just give you an idea how we work.
YOU ask how to perform, must be a trap, YOU are the guru...hmm..much more to say...
Cheers /Ingemar
-----Original Message-----
From: Stephen R. Gregory [mailto:[log in to unmask]]
Sent: den 6 september 2000 20:31
To: [log in to unmask]
Subject: [TN] HASL Dewetting...
Hi All!!
Got some boards in at receiving that are exhibiting dewetting on the pads.
You can see what I mean at:
http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures
I'm rejecting them of course, but what would be the most likely cause of
something like that? I'm pretty sure it's some form of contamination, but
what?
Thanks!
-Steve Gregory-
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