Electronics Forum | Tue Apr 24 02:56:12 EDT 2007 | chrispy1963
If the PCB you are using is a HASL pad finish and is a leaded assembly, we use homeplate pads with a 5 mil stencil. If the circuit has Enig finish and is PB-Free then we use 1:1 apertures with a 5 mil stencil Either method should provide no solde
Electronics Forum | Wed Oct 05 14:23:50 EDT 2005 | chunks
What kind of destructive testing is anyone doing for LF BGAs?
Electronics Forum | Mon Aug 02 08:54:15 EDT 2010 | vetteboy86
I believe it is LF HASL. I will need to double check.
Electronics Forum | Fri Jun 12 21:36:04 EDT 2020 | SMTA-Josh
Has anyone had an issue with changing from a HASL surface finish to a LF HASL finish if it is still being used in a leaded process? Also we are having issues with the planarity on the fiducials with the HASL finish. Are there any suggestions or ch
Electronics Forum | Mon Jan 29 10:41:10 EST 2007 | davef
Many high rel assemblers reball their LF BGA with SnPb balls. In other less demanding environments, SnPb paste with LF BGA produces acceptable reliability.
Electronics Forum | Tue Aug 03 17:13:41 EDT 2010 | bradlanger
Craig, If it is LF Hasl it sounds like it applied too thin exposing the intermetallic layer wich is not solderable. We call out a minimum thickness of 80 microinches and have good results. We have had shops in the past that did not control the Hasl
Electronics Forum | Tue Oct 23 03:57:39 EDT 2007 | jkhiew
Thanks Dave. But I do not understand why the solder being wicking away by the component itself. Does Ag/Pd finishes has stronger wettability than LF HASL finishes ? Rgds
Electronics Forum | Mon Nov 10 12:29:59 EST 2008 | joeherz
Dave, You've got me worried - All of the boards we've tested to this point are LF HASL. Why do you say "can't be ENIG"? Am I missing something? We have not sectioned soldered boards as yet but plan to shortly. Thanks.
Electronics Forum | Fri Aug 13 17:45:43 EDT 2010 | bradlanger
Boards with the LF hasl finish applied too thin will genrally pass the IPC test. That is some pretty agressive flux they call out. The boards usually wave solder just fine as well. Reflow is where the you see the problem.
Electronics Forum | Tue Jan 31 15:25:14 EST 2012 | joeherz
Hege, Yes. Good info. We have other products that run lead free process with known non-RoHS compliant components. All of these are using LF process compliant fabs however so this is the first time we have been in this position. Thanks.
