Electronics Forum | Sat Nov 08 08:16:45 EST 2003 | davef
We saw this quite a bit, I want to say 5 or 6 years ago, but it's probably more like 10 years ago. It's caused by poor solder mask crue. Talk to your board fabricator about solutions.
Electronics Forum | Fri Nov 07 12:48:31 EST 2003 | rholland
I have seen in the last couple of months more boards with a white hazing under the solder mask. I ran a few tests on a board to determine the cause of the white hazing underneath the solder mask. First I confirmed, or at least I think I confirmed, t
Electronics Forum | Sat Nov 08 09:42:22 EST 2003 | ethercom
Hi: I have seen this problem before. It is caused by improper curing of solder mask by the fab manufacturer. When you run the board thru' wave solder, and then wash the board, you see the problem of white residue. However, when you apply heat, you c
Electronics Forum | Tue Jan 03 17:36:49 EST 2006 | MikeF
If you know you have cleaned any flux residues that were under there you could consider a bead of an electronic grade RTV, such as RTV3145. If you trap any uncleaned residues under there you could have long term reliability problems. But, like Dave
Electronics Forum | Wed Aug 04 16:46:40 EDT 2004 | davef
We assume this is different discussion that the discussion about "crystallized flux under BGA". Correct? Milky residue with water washing makes us think "noclean flux res that just got washed". We know what you said, but we can't help ourselves.
Electronics Forum | Wed Aug 04 16:09:48 EDT 2004 | Dreamsniper
Hi, Thanks for your reply. I run 2 boards, using the same paste, thermal profile and the same method of aqueous cleaning, 1st is a Topline test board with topline BGA (BGA 272 with 1.27 Pitch) and the 2nd is our product PCB with our BGA from Motoro
Electronics Forum | Tue Aug 10 15:28:54 EDT 2004 | Shean Dalton
Because the HASL process most deal with bare metals, HASL flux residues are generally more active than solder paste residues. Typically a Rosin Active (RA) flux is used in the HASL process. These flux residues should be removed from the bare board
Electronics Forum | Wed Oct 11 15:40:34 EDT 2006 | Steve Gregory
Don't think there's any easy way to clean under a LCC, but you might want to consider this: http://www.winslowautomation.com/ccmd.asp A dead simple way to mount solder columns onto LCC's and then solder the part to the PCB with a stand-off of abou
Electronics Forum | Wed Aug 04 00:22:17 EDT 2004 | Shean Dalton
and one more thought about your original question, if the flux does look really strange and out of place, then inspect the reflow oven. A great amount of flux condensation in the reflow oven's cooling zone can cause crystalized flux to become airbor
Electronics Forum | Mon Aug 09 17:02:32 EDT 2004 | arminski
Hi Shean, Thanks for the analysis. "Your product looks like it may have non-solder-mask-defined pads." Yes. It is a NSMD PCB. "Does there appear to be any residues on the bare boards, and/or, BGA components prior to applying the solder paste?"
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