Electronics Forum | Tue Dec 31 08:07:28 EST 2024 | amorapotter
Consider the thermal mass of the PoP assembly. The upper BGA might be shielding the lower BGA from adequate heat. You could test with an experimental setup that pre-solders the lower BGA separately to confirm whether heat transfer during reflow is th
Electronics Forum | Fri Jun 23 10:01:35 EDT 2000 | Bob Willis
A couple of weeks back I produced a video clip for Metcal to show what happens when BGA pop or the edge of the base warps causing shorts to form. Its 2.3meg if there is enough interest in seeing this I will put it up some where for download. Bob Wil
Electronics Forum | Tue Mar 25 21:17:56 EDT 2025 | SMTA-64387381
Have you tried eliminating the flux dip on the lower BGA? At my last company, we assembled hundreds of thousands of POP devices. Never used flux on the lower BGA, just SAC305 with 4 mil stencil. Flux dip only on top BGA package using a Senju flux
Electronics Forum | Wed Nov 06 13:01:54 EST 2002 | cvrgirl
Hi, Has anyone experience BGA caps/plugs popped off after assembly on a double sided board? Only the caps on the primary side popped off and exposing copper. thanks! Michelle
Electronics Forum | Tue Feb 05 20:31:39 EST 2013 | hegemon
Air Vac DRS25. Hands down the best rework EQ. (my humble opinion, based on my own experience with rework EQ going back 15 years +) Right in your budget. Complete capability for rework. SMD, BGA, POP. Full profiling capability. Massive bottom heati
Electronics Forum | Mon Jun 26 23:33:20 EDT 2006 | KEN
We saw this condition over 3 years ago. It sometimes is called "champagne bubbles". The intemetalic formation is interrupted due to the micro voiding reducing mechanical strength. I discovered this on lead free test vehicles for a major computer
Electronics Forum | Mon Oct 25 21:49:14 EDT 2004 | davef
First, any results of pull or shear tests are unscientific at best. [We pop our BGA from boards with, appropriately enough, a beverage can opener.] Second, we have no have problems with your ENIG specification. Third, as with your customer, we'd e
Electronics Forum | Tue Dec 03 20:20:23 EST 2024 | cyber_wolf
Unless the PoP BGA has considerable thermal mass, then it's highly doubtful there is much of a temp delta from the circuit board to your ball interface. There are several things that can play into an insufficient solder situation. A few things to t
Electronics Forum | Sun Jun 23 23:23:25 EDT 2002 | beldorian
First question - I am making an assumption that after "de-pop'ing" a BGA prior to socketing the thing to test it, the best known practice is to re-ball the thing. Is this an industry standard? Second question - If it is an industry standard, does a
Electronics Forum | Thu Mar 13 19:35:40 EDT 2025 | ehess
I would double check your print. Most insufficient are caused by a bad print. What's your stencil thickness and smallest aperture size?
