Electronics Forum | Thu Apr 03 11:57:38 EST 2003 | davef
R4: We see the ball left on the PCB with a flat top and the BGA pad appears to be virgin. D4: Not good. The flat top indicates that the ball melted at one time or another. This pad and ball have seen at least two solder cycles with solder and flux. S
Electronics Forum | Thu Apr 03 09:48:31 EST 2003 | davef
R1: Contacting Altera to find out if the BGA pads are gold. D1: Bet money the pads were ENIG. R2: Contacting Altera to find out if they use abrasives. D2: If abrasives were the problem, you�d see it in many pads, especially those close to the probl
Electronics Forum | Thu Apr 03 09:08:50 EST 2003 | rdr
Thanks Scott,Iman, The problem has been isolated to detachment from package so I believe that there are no fabrication issues related to the Gold on the PCB. What is a Moyet analisys? where can I find more info? Dave, I am still waiting on Altera t
Electronics Forum | Tue Apr 01 08:59:06 EST 2003 | rdr
Hi all, I've got a question that hopefully someone can provide insight. We have a gold immersion assembly that we believe is experiencing fractures or non wetting on a certain BGA. To be sure that it is a fracture and not a wetting issue I would li
Electronics Forum | Tue Apr 01 17:29:58 EST 2003 | davef
R1: So if I understand you right, it could be possible that gold dissolved, but the ball still didn't wet to the underlying nickel. D1: Correct. The gold dissolves into the solder first. The solder wets to the nickel second. If you nickel is corro
Electronics Forum | Thu Apr 03 11:17:17 EST 2003 | rdr
Well, first off now I'm just starting to believe that we are fracturing again. But here is some more input D1 ENIG? I would not have thought that they would be but as usual you are probably right. D2 Again I would have to agree about it should affe
Electronics Forum | Wed Apr 02 23:02:38 EST 2003 | scottf
I agree with Iman. Verify the integrity of the component for moisture. Most definately place an amount of ownership on your PCB supplier. Request tank analysis results and copies of the lot travelers. Look specifically for any in process rework pro
Electronics Forum | Tue Apr 01 11:50:08 EST 2003 | rdr
Dave, thanks for the info. This sounds like it would verify the presence of an open. We have verified that these balls are open and I am trying to figure out if we are fracturing or not wetting. causing these opens. I would use the die method on ne
Electronics Forum | Tue Apr 01 19:36:02 EST 2003 | iman
from my humble experience : 1) check if there is nickle contaminate in the gold bath? shd have report data from the PCB fab house. 2) check if your production did 48hr bake at 125degC, IF the BGA did not come in its "original" MSD cozy packaging.
Electronics Forum | Wed Apr 02 09:25:32 EST 2003 | davef
RDR The most common cause of dewetting is from a fabricator using any form of abrasive (e.g. pumice, abrasive brushes etc.) on copper. With this process, abrasive particles get implanted into the copper (often actually swaging copper over some of th
