Electronics Forum | Tue May 17 10:01:42 EDT 2005 | russ
I have had the same problem with this supplier, we found that one mfg. place or process used a .015" piece of FR4 as the base while others had .030" Fr4, We discontinued use of the .015" and never had a problem again.
Electronics Forum | Tue Feb 18 19:07:21 EST 2003 | arturoflores
Our case is not due to thermal pad print squeezing because our shorts are mostly in the outer rows of the BGA so they cannot be caused by central pad printing. We still stick to the BGA thermal pad coplanarity/height hypothesis but have not yet prove
Electronics Forum | Mon May 16 12:42:59 EDT 2005 | adrian_nishimoto
We have a customer that has been trying to place the Xilinx part number XCV2000E-6FG1156I which is an 1156 ball plastic BGA. When we do the X-ray and inspection we find that the package is warping up on all four corners of the package, Like so: Top
Electronics Forum | Tue Feb 18 22:15:04 EST 2003 | davef
Arturo, So, you're not shorting to a thermal pad. Given that you're shorting to outer balls, tell us about: * Location of the shorting among the outer balls. * Board construction. * BGA constuction. * Paste deposition. * Temperature measurements ta
Electronics Forum | Thu Aug 27 13:14:49 EDT 2009 | ghepo
I have already told you that is not possible solve this problem by e-mail, without perform a detailed failure analysis. Also I have told you to procede by exclusion. Are you sure, by tests, regarding the PCB quality ? Are you sure regarding the solde
Electronics Forum | Mon May 16 15:29:53 EDT 2005 | jdumont
We have the exact same issue with out 456 ball Xilinx parts. The corner balls either do not touch or are so stretched out that they are intermittant. I believe this to be a moisture ingress problem. Ive been setting up our little batch oven this afte
Electronics Forum | Tue Feb 18 16:31:43 EST 2003 | arturoflores
Haran: Have you made improvements regarding your BGA shorts? We are facing the same problem and we think it is partly because the non coplanarity of the seating plane of the BGA which causes BGA balls to squeeze on one side of the BGA. Also, we ha
Electronics Forum | Mon Nov 01 07:39:49 EST 2004 | Bob R.
Yes, you can place a BGA in flux and get good reflow. However, depending on BGA type and size you should expect a yield loss due to coplanarity issues. Having the paste on the pad definately helps your yield.
Electronics Forum | Tue Jun 26 12:24:24 EDT 2001 | nifhail
Thanx for the reply Dave. We actually had a few thermocouples attached from underneath to see if there is any delta in temperature within the same BGA's ball. They looks OK, with the slope of 1 -2 Deg C,soak at 120 Deg C - 150 Deg C at about 90 sec,
Electronics Forum | Tue May 17 08:00:26 EDT 2005 | Bob R.
We went through this with one PBGA supplier recently and they were able to get the problem under control by fixing some of their molding processes that were inducing residual stresses. You can really see it in a thermal moire where you measure warpa
