Electronics Forum | Fri Apr 05 15:24:14 EDT 2019 | sever_83
What can cause solder balls to appear after conformal coating? Using Dymax 9-20557, light curing for 1.5 mins. Can too much heat from light cure cause solder balls?
Electronics Forum | Fri Apr 05 16:31:55 EDT 2019 | slthomas
Never heard of such a thing. Are you sure the coating isn't just making the solder balls more prominent? Where are the "new" solder balls appearing after coating?
Electronics Forum | Mon Apr 08 14:16:29 EDT 2019 | sever_83
We've never heard of seen of such a thing either. We tried a clean sample board and applied con coat. Same process through out and we saw nothing. After speaking with the original operators who was curing the boards he had left the boards much longer
Electronics Forum | Wed Mar 27 21:20:30 EST 2002 | davef
There is two major BGA coating camps. * Camp #1: "We require the coating to be under low stand-off devices but with no filleting. So we apply a thinned dip coat first, and then top-off with a proper spray coat" * Camp #2: "We want no coating under th
Electronics Forum | Fri Jun 19 15:17:54 EDT 1998 | Chris Jackson
We are in the process of validating Silicon 1C55 (thermal cure) conformal coating over Alpha LR725 solder paste. I am looking for anyone who may be using this process, or has been exposed to someone who is doing this process. Our concern is with the
Electronics Forum | Wed Sep 30 11:32:45 EDT 2009 | pbarton
What type of conformal coating are you using and are you allowing the coating to migrate under the device in question? If you are allowing the coating unbder the BGA the problem could be CTE of coating is much greater than that of the BGA balls/sold
Electronics Forum | Thu Oct 01 07:03:55 EDT 2009 | davef
We doubt that Humiseal 1A33 is causing opens in your assemblies. We'd guess the opens occur earlier in the process, but are not hard failures. So, you pass your tests. When applied, the conformal coat flows into the gap in the ball crack and insulate
Electronics Forum | Thu Jan 13 09:18:28 EST 2005 | davef
We agree that coating BGA solder balls with conformal coat is a bad idea due to differences between the z-dimension thermal expansion between the conformal coat and solder.
Electronics Forum | Mon Sep 21 20:45:55 EDT 2009 | davef
10.4. Pre-Cure Examination. Immediately after material application, the uncured conformal coating shall be examined for: a. Bubbles and Air Entrapments. These defects shall be broken by vacuum, with a sharp probe, or other appropriate tools. b. Bridg
Electronics Forum | Wed Jan 12 13:27:42 EST 2005 | carobin
The two options I see are (not including underfill): 1) Have complete conformal coating coverage of all balls with no webbing in between balls because of CTE mismatches. If all the balls are not coated we see failure in humidity testing. or 2) Sea
