Electronics Forum | Thu Dec 24 09:32:53 EST 1998 | Earl Moon
| Anyone ever attach gold bump flip chip to FR4 or Alumina substrates. Am trying to find a solder which is acceptable for use on gold. Am worried about gold imbrittlement since the gold bumps on the flip chip are .004"x.004"x.001" solid gold. The p
Electronics Forum | Thu Dec 24 13:29:19 EST 1998 | Chris Grendler
| | Anyone ever attach gold bump flip chip to FR4 or Alumina substrates. Am trying to find a solder which is acceptable for use on gold. Am worried about gold imbrittlement since the gold bumps on the flip chip are .004"x.004"x.001" solid gold. The
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 Mar 18 11:27:24 EDT 2020 | slthomas
I am about to order a stencil and I can already see that I'm going to have issues. I'm hoping someone has a recipe for this scenario that we haven't tried yet. The parts are 16 mil pitch bga's, the pads are NSMD (10 mil dia. with 12.6 mil mask open
Electronics Forum | Tue May 28 09:27:04 EDT 2002 | pjc
Does this PBGA have eutectic balls? If so and the PCB is HASL finish, or has solder on the lands from BGA removal, you may not have to apply solderpaste. Check with you flux supplier to see if they offer a NC "flux paste" product, otherwise I know Mu
Electronics Forum | Tue Sep 14 14:07:45 EDT 2010 | grahamcooper22
Hi Gani, HASL is normally very good for solderability providing there is a good consistent coating of HASL on the pcb pad. But it is not unusual to have a very thin coating of HASL on the pad and this is poor for solderability. You then have tin/copp
Electronics Forum | Tue Sep 19 13:09:48 EDT 2017 | slthomas
Thanks, all, for your responses. It's always helpful to know what everyone else is doing, whether to validate your own experience or to force you think in more detail. At this point we've determined that no amount of aperture design, material contr
Electronics Forum | Tue Sep 19 09:41:30 EDT 2017 | sumote
Steve, The 4 things I would do, and in this order: 1. Clean your stencil with stencil cleaner wipes after it comes out of the stencil cleaner. I like MicroCare ProClean (MCC-PROWR). I will even saturate the wipe with a bit of isopropal just till
Electronics Forum | Wed Feb 23 21:35:01 EST 2000 | Dave F
Larry: You're correct to question this: * We don't like to run raw paste through our aqueous cleaner. It makes a blinking mess. Your entire machine is probably now coated with hazardous material ... well at least the first tank and the out-bound
Electronics Forum | Wed May 31 23:19:15 EDT 2000 | Jackie Hsieh
I think the reasons of the tombstone phenomenon could be concluded as follows: 1.The proper pad size,including the dimension of two pads,the gap of two pads. 2.The temperature distribution must be uniform (take care the shadow-effect) 3.The ramp-up s
