Electronics Forum | Tue Feb 07 19:10:04 EST 2006 | GS
Hi, other effect could be the extra inter-metallic thickness that could compromise the solder joint reliability. just my 0.00001 Doblon Best regards.........GS
Electronics Forum | Tue Apr 18 03:40:05 EDT 2006 | Slaine
Did you try tensile testing after thermal cycling? If there are any intermetalic problems between the two alloys this should show it.
Electronics Forum | Tue Jun 13 13:42:34 EDT 2006 | Bob R.
Also be careful in assuming you have black pad. A nice straight crack along the Sn-Ni intermetallic is probably just overstress at some process (most likely ICT). The better board suppliers figured out how to avoid black pad years ago.
Electronics Forum | Fri Jan 26 11:18:54 EST 2007 | samir
Chunks! Good to see you here. From what I've been taught, and from what I've read, the strength of the solder joint is in the intermetallic bond which occurs at the atomic level. A solder FILLET is an indicator that wetting took place.
Electronics Forum | Wed May 02 07:47:21 EDT 2007 | Bob R.
Don't dink with the profile until you have evidence that the profile has something to do with the problem. Step 1 is a cross-section. Where are the joints breaking? Do the joints show signs of proper wetting & intermetallic formation?
Electronics Forum | Fri Sep 28 07:42:07 EDT 2007 | zanolli
We have the need to verify that proper intermetallic layer between a 100% Sn plated contact and the solder joint is being formed. Never having done this before: Is there any specifications, etc. that we can use as acceptability criteria?
Electronics Forum | Tue Apr 15 13:08:58 EDT 2008 | abaumann
If the solder had formed an intermetallic then it couldn't have pulled off completely like it did, it's obvious that the boards have a problem with their finish.
Electronics Forum | Wed Jul 02 08:06:10 EDT 2008 | ck_the_flip
Yes, your strength of the joint is in the intermetallic, and not additional solder. Solder ain't like duct tape, where the more you put, the better it'll hold.
Electronics Forum | Wed Sep 03 07:36:39 EDT 2008 | vladig
That is why it has to be a few micron thick. Otherwise, it will form a layer of intermetallic which is extrremely difficult to solder to. Vlad
Electronics Forum | Sat Sep 12 10:12:20 EDT 2009 | tylaburg
My customer wants an SnPb 63/37 BGA soldered using SAC305 solder paste. What data is avaiable showing the long term reliability of the intermetallics of the solder joints?
