Electronics Forum | Mon Oct 02 20:17:38 EDT 2006 | davef
The different coefficient of expansion of materials used in some BGA can cause warping issues. We've talked about this previously on SMTnet. Search the fine SMTnet Archives. For instance: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=2
Electronics Forum | Mon Oct 02 05:45:41 EDT 2006 | Thomas
Hello, Have anyone of you any experience of mounting BGA-s on both side of the PCB in lead free process? Have you seen any problems after the second reflow? Is it something special to focus on? /Thomas
Electronics Forum | Wed Oct 04 09:55:51 EDT 2006 | borgie
Hi. I have product in lead containing process that consist lead free BGAs and also big ceramic BGAs with high temperature bumbs. Pcb tends to bow in a reflow profile, since I need long preheating times and relatively high peak temperature to melt BG
Electronics Forum | Mon Oct 30 21:00:31 EST 2006 | hanocete
thanks for your inputs,but what i meant was that a connector component beside the BGA for repair has some flux residue on its leads after baking, the BGA was Ok. we are wondering why this happened...pls enlightened us.
Electronics Forum | Wed Nov 08 10:12:07 EST 2006 | markhoch
Thank you for the Best-Tronics Suggestion. I checked out their website, and although they look to be extremely capable when it comes to cable assemblies, I saw nothing on the website that referenced SMT or BGA assembly or rework.
Electronics Forum | Wed Nov 15 00:42:43 EST 2006 | Jp
I tend to agree with process science's rec. They are currently doing a board with stacked BGA, and the board is around 18 by 18. Good luck.
Electronics Forum | Wed Nov 29 01:12:12 EST 2006 | callckq
Dear Davef, Thanks for your input...The crack happen at the pad/solder ball interface..Pls review the new thread that I post just now with title called "BGA BALL CRACK AT PAD/SOLDER BALL INTERFACE" Thanks!
Electronics Forum | Thu Dec 07 14:23:30 EST 2006 | russ
I wuld say it is attachment method and post install force that is the problem not the size of the heatsink. we place heatsinks that are at least 5 times the size of BGA with no issue, they are attached with very precision torque drivers. Russ
Electronics Forum | Thu Dec 07 12:18:28 EST 2006 | realchunks
It may be for a double sided reflow process. Yes, some people do put the BGA on first. I know this first hand.
Electronics Forum | Thu Dec 07 14:17:03 EST 2006 | russ
I would bet that it is a SMT adhesive used to ensure that the BGA does not move during a secoindary reflow prcess. this glue is easily removed with a soldering iron. Russ
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