Electronics Forum | Tue Nov 10 07:35:04 EST 2009 | scottp
Step 1 is to find out what kind of opens you're getting through a cross-section or die & pry. Are they head in pillow, brittle fracture at the intermetallic, bulk solder cracks, ball separation from interposer? Without some basic failure analysis a
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 | Mon Oct 04 07:48:34 EDT 2010 | scottp
When you break them where is the failure? Is it the solder joint (doubtful), the part termination, the body of the part, or the board? If in the solder joint, is it in the bulk solder or intermetallic? If in the part, what direction is the crack?
Electronics Forum | Wed Apr 13 17:19:44 EDT 2016 | davef
Formation and Growth of Intermetallics at the Interface Between Lead-free Solders and Copper Substrates [ http://www.boulder.nist.gov/div853/Publication%20files/NIST_Apex94_Siewert.pdf ]
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 | Mon Jun 21 12:57:10 EDT 1999 | Earl Moon
| | I dug through my big box of office crap and found the disk with my technical papers. I posted the one on process control in the SMTNet library. It covers a lot of ground on what causes defects in the wave (too much or too little of something),
Electronics Forum | Mon Jun 21 13:02:59 EDT 1999 | Earl Moon
| | | I dug through my big box of office crap and found the disk with my technical papers. I posted the one on process control in the SMTNet library. It covers a lot of ground on what causes defects in the wave (too much or too little of something)
Electronics Forum | Mon Jun 12 22:00:51 EDT 2000 | Dave F
Could be. What are your profiles? 2) Au finish fail => Could be, but that the connections can be made with hand soldering makes this a low probability cause, assuming the activity of the flux used in hand soldering is not significantly different fr
Electronics Forum | Thu Oct 25 16:48:29 EDT 2001 | Cemal Basaran
We can inspect and measure strain field in anything larger than 320nm with Laser techniques we have. We can do this measurements during fatigue testing. Of course thick intermetallic region as a solid region is a problem due to the fact that you ha
