Electronics Forum | Wed Nov 02 01:30:12 EST 2005 | fctassembly
Hello Arnold, Yes, by definition of joint formation, copper will dissolve in lead free solder in order to form the connecting intermetallic layer. There is a distinct difference in the copper dissolution rates of the major alloys being considered wi
Electronics Forum | Fri Dec 09 07:10:36 EST 2005 | Mity-C
Good Morning, One problem of LF BGA's in a leaded process is the temps required to propperly collapse the BGA balls. If the BGA is LF, the alloy of the balls will not reflow until the temp reaches 217-245 C. SN 63/37 reflows at 183 C. If your profil
Electronics Forum | Fri Sep 22 09:45:26 EDT 2006 | bradlanger
Greg, All the above. It looked like it was going to be a drop for SNPB HASL at first but after a few thousand boards we started running into all the problems you are describing. We first started seeing non wetting on SMT pads. The solder would wet t
Electronics Forum | Thu Oct 05 11:48:00 EDT 2006 | Mario Scalzo, SMT CPE
Good morning all. We are able to offer some insight into the problem and offer a recommended reflow profile to solve this issue, but it really depends on the solder paste that you use, as different manufacturers use different boiling point solvents.
Electronics Forum | Mon Jan 29 10:11:12 EST 2007 | muse95
What does your customer want you to do? I would not want a CM soldering one of my boards with leadfree paste if I didn't ask him to. Whatever you do, get approval first. Two things to consider: If the other components are not rated for leadfree tem
Electronics Forum | Tue Apr 28 08:51:35 EDT 2009 | davef
This is a snip from an ealier post here on SMTnet. Generally, solder pastes are comprised of: 90% solder powder, 5% flux, 4% solvents, and 1% activators [by weight]. Where: * Solder powder, when reflowed, is a metal bonding agent that mechanically
Electronics Forum | Wed Jan 17 03:35:07 EST 2001 | Arul
We have few failures similar to the discussion in this thread, on a 50 Mil pitch, 30 Mil mill Ball PBGA. Would like to understand the mechanism of the BGA reflow process bit more. Appreciate your response to the following. 1.We sheared few solder ba
Electronics Forum | Wed Jan 17 20:48:14 EST 2001 | davef
We find that the raw BGA's pad sheared surface has the SnPb solder at various Z heights whereas the assembled BGAs pad leave a smooth layer of SnPb along the pad. Like to understand the cause for the difference. Who could guess? Solder joint streng
Electronics Forum | Thu Jan 18 21:52:24 EST 2001 | arul2000
>>>>Dave, The BGA substrate surface finish is NiAu, while the PCBA pad surface is HASL. The solder ball composition is SnPb 63/37 and the solder paste used on the PCBA is also the same but with 2% Silver.>>> Dave, sorry I don't have the picture with
Electronics Forum | Thu Feb 10 22:41:20 EST 2000 | Dave F
Russ: Now that�s a good story. Nuff said on the Vegas trip, that explains everything. Especially when you say "it must have something to do with ..." I love WS609. It�s been berry, berry good to me. Intermetalic Layer (IL). A compound formed a
