Electronics Forum | Tue Sep 25 14:08:59 EDT 2001 | davef
Oooo, the solder on the pad and PGA ball is flowing during reflow down the via to the secondary side? Why didn�t you say so?? ;-) Why would you expect that gravity and capillary action wouldn�t force solder to flow down the solder plated via to the
Electronics Forum | Fri Nov 23 16:32:05 EST 2007 | davef
There a several things you can do to prevent the solder wicking down the hole with the current design, and that's where you should focus. Cost goes up as you go down the list, but in neither case do you need to respin the board, have solder starvatio
Electronics Forum | Thu May 05 09:46:04 EDT 2005 | davef
Board fab, Defects, Pad coatings, Gold black plague articles 1 Nick Biunno's article: http://www.nukcg.org/downloadfiles/Hadco%20on%20Immersion%20Gold%20failures.pdf 2 George Milad's article: http://www.circuitree.com/ct/cda/articleinformation/featu
Electronics Forum | Fri Aug 02 12:07:50 EDT 2002 | johnw
Richard, your asking a multi million dollar question that in my own opinion no one can give you the right answer since no one really knows. hence I think the lack of answers to your question....thought there would be more people willing to propose a
Electronics Forum | Tue Apr 27 07:46:14 EDT 2021 | jeremy_leaf
I have tried cleaning the pads. That was our first step. Ultrasonic cleaning in acetone and IPA, and also tried etching in a 10% HCL solution. Our board is definitely achieving the correct temperature.
Electronics Forum | Thu Aug 15 15:58:12 EDT 2002 | robertnguyen
To whom this may concern, I recently ran into the problem with vias on pads of BGA when place BGA and reflow gas trap on vias escape and result in ball having void greater than 50% of BGA diameter. The BGA pad is measured at 20 mils and the vias mea
Electronics Forum | Fri Aug 16 09:59:49 EDT 2002 | dason_c
We baked the board first and print 2 mil water soluble paste at the BGA location and reflow. Wash and baked before the production run.
Electronics Forum | Wed Dec 08 17:58:44 EST 1999 | Dave F
Dave: You should see a solder smudge on the gold plating where the ball was attached, if there is (was) solder reflow during either the (1) BGA fabrication, (2) your BGA attach, and / or (3) your BGA removal. You rework will not remove the solder
Electronics Forum | Tue Dec 07 20:07:21 EST 1999 | Dave C.
Thanks for all the info Dave. It's the interconnect between the copper foil pad and the eutectic solder ball that I'm most interested in. The BGA in question is very thin gold plated over nickel over the copper. When we are reworking the BGA, i
Electronics Forum | Fri Dec 03 18:17:12 EST 1999 | Dave F
Dave: There's lots of stuff on the web describing BGAs. Examples are: http://www.smtnet.com/bookstore/publications/0speckdo1/s1.html http://www.smtnet.com/bookstore/publications/0shutcco1/ch1p2.html http://www.citizen-america.com/OEM/bga/process
