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
Technical Library | 2016-09-08 16:27:49.0
In this investigation a test matrix was completed utilizing 900 electrodes (small circuit board with parallel copper traces on FR-4 with LPI soldermask at 6, 10 and 50 mil spacing): 12 ionic contaminants were applied in five concentrations to three different spaced electrodes with five replicas each (three different bare copper trace spacing / five replications of each with five levels of ionic concentration). The investigation was to assess the electrical response under controlled heat and humidity conditions of the known applied contamination to electrodes, using the IPC SIR (surface insulation resistance) J-STD 001 limits and determine at what level of contamination and spacing the ionic / organic residue has a failing effect on SIR.
SMTnet Express, Septemeber 8, 2016, Subscribers: 26,370, Companies: 14,943, Users: 41,052 How Clean is Clean Enough – At What Level Does Each of The Individual Contaminates Cause Leakage and Corrosion Failures in SIR? Terry Munson, Paco Solis
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