Electronics Forum | Fri Jun 07 05:08:08 EDT 2019 | gregoryyork
Does look like delam, if its that bad and the board looks like its HASL finish or Silver, it could also be porous absorbing the chemistries of HASL or Nitric from the Silver which will greatly encourage ECM or poor SIR figures or just simply eat the
Electronics Forum | Fri Jun 07 11:17:14 EDT 2019 | teejsd
Unfortunately for me, I can't say whether those balls were flat on 1 side or not -- sent this board for x-section to see if we had CAF, since my ionics testing wasn't breaking IPC standard. Unhappily my x-sect results were inconclusive. However I d
Electronics Forum | Fri Jun 07 11:31:11 EDT 2019 | teejsd
This does sound like my failure! Failure typically goes away when boards are removed from humidity. Yes we do have a HASL finish. Do I have to do the waterbath alcohol/water extraction to pull these contaminants, or is warm water/steam enough?
Electronics Forum | Thu Jul 12 10:23:30 EDT 2012 | blnorman
Check with your adhesive manufacturer. In a previous life we had one line that was either double sided reflow or wave following reflow. When it was ds reflow, we just shut off the wave. When it was reflow/wave, we kept the reflow oven on with the
Electronics Forum | Thu Apr 04 20:21:57 EDT 2019 | teejsd
We're testing this PCB in 40C 93RH to see if we get ECM or CAF. We have failure. I traced it back to the vias on the left (signal & gnd)if I can get the picture to load. We have not yet confirmed or denied CAF. I am wondering if I should be concer
Electronics Forum | Fri Jun 07 11:19:14 EDT 2019 | gregoryyork
If you have soldered with HASL finish then the worrying chemistry will be more like NON IONIC. They sit there and attract moisture like mad and any chlorides they hold ionize in the moisture attracted and cause electromigration or SIR issues. They ca
Electronics Forum | Fri Jun 07 12:34:30 EDT 2019 | teejsd
C3 just uses heated DI water that it applies, then pulls back into a disposable cartridge. Machine then applies a 10V charge to the sample & measures leakage current(nA,I think) over time(sec). If the leakage current is high enough/fast enough, you
Electronics Forum | Fri Jun 07 12:44:55 EDT 2019 | gregoryyork
These residues are extremely water miscible BUT you will probably need the extraction of heated IPA/Water to get the porous resist to release the residue quicker than it would do releasing it naturally in the field. Why dont you try to soak the circu
Electronics Forum | Fri Jun 07 14:14:24 EDT 2019 | teejsd
Yes neither our HPLC IC nor our C3 could detect any concerning levels of ionics. Soaking over a weekend sounds like a good idea, though I may still need to cut the board down to fit our Kapak bag size. And get our silicone coating off the surface. K
Electronics Forum | Fri Jun 07 11:39:33 EDT 2019 | gregoryyork
I feared so. The only thing to be done is to tell the PCB manufacturer to increase the Thermal cure so dont set the oven to 150C but to 170C and actually measure the middle board and once it hits 155C then give it an hour cure from then. Also insist
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