Electronics Forum | Thu Feb 20 17:18:24 EST 2003 | davef
Give us infortmation, please. What is [are]: * Height board to board side of the interposer on the low side of uBGA * Height board to board side of the interposer on the high side of uBGA * Alloy of solder balls, no paste was used correct? * Type of
Electronics Forum | Wed Jan 03 12:33:37 EST 2001 | Terry Burnette
John, There is one process issue that occurs with the larger BGA packages which have coplanarity near the high end of the .2mm spec.. The defect is commonly referred to as "ball in cup" and "head in pillow". It is an open solder connection whereby th
Electronics Forum | Fri Dec 17 15:11:34 EST 1999 | Alvin Kevichusa
Let's look at it this way... Imagine a multileaded component sitting on a flat surface. If all the leads touch the flat surface, they are all in the same plane (that of the flat surface) and are coplanar. Coplanarity is desirable because if a lead is
Electronics Forum | Fri Mar 21 08:56:29 EST 2003 | russ
Is it possible that the flux you used, if applied in excess could have caused the balls to "blow out". I have seen this in the past and it was related to the type of flux we were using and the amount. Russ
Electronics Forum | Mon Mar 24 08:57:20 EST 2003 | russ
I don't know if I would call it a "blow hole". what I believe happens (I don't have a camera to watch spheres during the reflow process) is that when the flux starts heating up, expansion, bubbling, or something physically displaces the balls. We fo
Electronics Forum | Tue Jun 04 22:54:32 EDT 2002 | davef
Solder balls are one of the most popular topics here on SMTnet. Search the fine SMTnet Archives for background. We like to wash solder balls from the board in our cleaner.
Electronics Forum | Tue Dec 31 02:04:19 EST 2019 | sssamw
From the picture, I cannot see clearly solder ball violate electrical clearance or cause a short, maybe it is. What I can see is the solder paste has some misalignment although it doesn't printed in solder mask area, but actual position will reduce
Electronics Forum | Wed Jan 01 22:19:33 EST 2020 | sssamw
Solder ball attached on solder joint without violation minimum electrical clearance is acceptable. If your process parameter including stencil not changed, suggest you check if solder pasted being pushed out after IC placement, also check if solder j
Electronics Forum | Tue Dec 31 02:06:21 EST 2019 | sssamw
Yes, from the picture, it seems the gap between solder pad is very small, easy to have solder ball/solder bridge.
