Electronics Forum | Tue Mar 25 11:25:18 EDT 2014 | horchak
The first impression I get is that the mask was applied over dirty or contaminated copper. What is the trace and land finish on the PCB? You also appear to have a wetting problem.
Electronics Forum | Fri Jun 07 11:10:08 EDT 2019 | teejsd
We also have a Foresite C3 for spot testing for ionic contamination. I didn't use it at this spot, but used it some other spots around the PCB that showed this color change and with our C3 we were passing IPC standard for ionics. But I was wonderin
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 | Wed May 26 06:59:10 EDT 2004 | davef
Some peelable solder masks attack immersion finishes. It appears components in the peelable soldermask, such as ammonia, are not very friendly to these particular surface finish. [We've wanted to investigate the effect of mask application thickness
Electronics Forum | Fri Apr 16 12:17:51 EDT 2010 | richardli
We have asked the supplier use whiter soldermask taking more heat. We also asked the board supplier to double coat board with soldermask. All these tries failed. We are wondering if the stains are flux contamination.
Electronics Forum | Mon Jan 26 07:27:43 EST 2004 | loz
I have a product that has earthing/positioning holes, as they are to be used for earthing purposes they need to be free from conformal coating. This pcb is double sided. I have used spot/peelable mask to protect these holes. However when the conforma
Electronics Forum | Mon Mar 20 15:48:52 EST 2000 | Shane Lay
We are planning on converting to a no-clean soldering chemistry and will need to replace our water soluble liquid solder mask as a result. Does anyone know of a dispensable, "peelable" solder mask I can evaluate? It would be nice to find one that i
Electronics Forum | Thu Nov 10 02:04:26 EST 2011 | julien
We've got the same problem here, what we do is to apply peelable solder mask around the connectors or the exclusion zone. But be carefull! Sometimes the soldermask get inside the connectors and you can't remove it so you have to change it. Another th
Electronics Forum | Fri May 18 13:08:19 EDT 2012 | blnorman
I'll chime in here as well. If you have adhesion problems, 90% of the time it's contamination on the substrate (soldermask, flux residues, cleaner residues, etc.). Like Dave said, omega meter is a test for gross cleanliness, and it's OK for process
Electronics Forum | Thu Oct 14 17:14:39 EDT 2004 | mattkehoe
We are experiencing a problem with soldermask defined BGA pads not accepting solder during the reflow process. The paste is there when the boards come off the printer but after reflow, no paste. Some other pads in the same pattern are fine. Here is t
