TechNet,

    We have some SMT CCAs which we receive with Entek OSP coating. The vias on
the PWB are not solder masked nor during assembly processing are they screened
and pasted. After convection oven reflow, is there still some Entek on the vias
or is the OSP removed by the processing?

The CCAs are later conformally coated which puts down 1-5 mils of type AR
protection on the vias. However the vias underneath large QFPs do not get
conformally coated by the Nordson sprayer. Is there a reliability concern here?

Also, after 120 hours of humidity/temp cycling, the tin-lead pasted areas
exhibit some white residue while the non-solder masked and non-conformally
coated Entek areas appear fine.

In anyone's experience, is there a long term issue for Class 3 goods?

Stu Korringa
Smiths Industries
Grand Rapids, Mi
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