Electronics Forum | Wed Nov 06 16:31:59 EST 2002 | slthomas
I would also consider paste control (don't take it personally...I always have to get after people about this one), time on the stencil, time between print and reflow, solderability of the component leads, paste volume (that one really got us once....
Electronics Forum | Fri Apr 29 14:16:16 EDT 2011 | ppcbs
Below is the long explanation. This defect is most commonly found with BGA components, but can arrise with all components. I see it happening more now with lead free boards that are being assembled with a no clean flux. Best short term remedy is t
Electronics Forum | Thu Nov 15 09:29:03 EST 2007 | jaimebc
Just to add to the subject, we experienced insufficient solder on our QFN's at our prototype level. To correct it, we went to a 5 mil stencil, 20% reduction on QFN pertures and used QFN's with solder bumps on the pads. We had great results using thi
Electronics Forum | Fri Nov 10 22:31:27 EST 2017 | myke03o
Hi, we are experiencing insufficient solder and bridging solder. Any recommendation on the inner pad (LGA) and stencil thickness. Any suggestion will be very helpful. link: http://www.latticesemi.com/~/media/LatticeSemi/Documents/ApplicationNotes/
Electronics Forum | Thu Oct 28 09:25:35 EDT 1999 | Dave F
Chris: Typical non-wetting causes are: * Poorly controlled soldering process * Incorrect material * Surface contamination * Insufficient preheat * Misapplied solder mask * Shadowing Without intending to insult you, all of the causes of non-w
Electronics Forum | Fri Jul 13 18:25:09 EDT 2007 | seankim10
It sounds like more has to do with plating. you may also check out the voiding issue especially if you have new FAB or the supplier. I had problems with a RF chip in QFN package due to insufficient grounding that voiding caused. This ground is often
Electronics Forum | Thu Jul 05 13:47:10 EDT 2007 | arun2382
QFN assembled on a PCB indicates paramteric fails when tested. When the QFN on PCB is reflowed a second time, it recovers and passes testing. Visual, X-ray inspection revealed no anomalies. Cross-section images of solder joint revealed no anomalies (
Electronics Forum | Wed Nov 15 12:52:21 EST 2017 | georgetruitt
IMO – Look into nano-coatings for your stencil and radius all square apertures This should help out with solder paste releasing from the stencil helping with insufficient solder QFN LGA aperture design, try a stencil cut with a few different apertur
Electronics Forum | Wed Jan 17 10:14:37 EST 2007 | slthomas
2-3mm would seem close enough to affect the air flow and I was thinking it could be displacing the qfn. However, if you ran a failed board back through reflow and it was functional after that, I'd put my money on insufficient reflow. I suppose it's
Electronics Forum | Tue May 31 09:40:23 EDT 2005 | mattkehoe
We have some boards that exhibit poor solder wetting when reflowed. Nothing fancy, smallest pitch size .050. See photo's at http://www.sipad.net/SnPbwetting.htm Is this ; Contamination on the HASL finish? Insufficient solder,not enough to cover pad
