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 | Fri Dec 27 09:45:04 EST 2002 | emeto
what exactly do you mean by big thermal pad?
Electronics Forum | Fri Dec 27 10:04:56 EST 2002 | haran
Big pad located at the middle of the package. On the PCB,we need to have solder paste printed on the thermal pad which is at the middle and the other pads of the perimeter BGA.
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 | Fri Dec 27 01:30:13 EST 2002 | haran
Currently we are running a BGA with a big thermal pad in the middle of the package and encountered high defect of solder shorts.I would like to check whether anyone has experience this problem and how this can be rectified?.
Electronics Forum | Sat Dec 28 02:58:12 EST 2002 | emeto
If the problem is in the big thermal pad.The surface strains in that pad are different then the others and through the reflow period there is an affinity between them(only if they are too close). I recommend you to reduce the theramal pad. Make smal
Electronics Forum | Fri Dec 27 14:11:18 EST 2002 | cnotebaert
We have placed these parts. I have not had problems with them but when I designed the stencil we reduced the app for the large thermal by 20% to reduce the chance of problems like your having. If the balls are close (.040-.050" or
Electronics Forum | Wed Feb 19 19:24:12 EST 2003 | arturoflores
Is there any way I can attach a report?
Electronics Forum | Mon Dec 30 13:52:50 EST 2002 | bcceng
Haran, This problem can also be caused if the BGA package is POPCORNING. Popcorning causes the BGA package to expand below the die, seen this happen so often to customers that try to install BGA's themselves without the proper handling of BGA's. Tha
Electronics Forum | Wed Feb 19 22:08:21 EST 2003 | davef
We usually end-up emailing reports and pix to each other. Fire a copy off to me.
