Hello all,
Sort of a rehash of last week's question, but here we go...
I have bare boards, .062 thick, double sided, LPI solder mask, that are a
HASL finish.
There is solder adhered to the (soldermask coated) conductors, and also to
the LPI between conductors. On the last batch of boards, the fabrication
house was of the opinion that this wasn't a defect where there was solder on
the conductors.
Unfortunately I don't have IPC specs in front of me to pore through, but on
our fab drawing, we reference the following:
Latest version of all referenced specifications to be used.
Fabricate in accordance with IPC-A-600, class 2.
Inspect in accordance with IPC-6012, class 2.
Use LPI solder mask over bare copper per IPC-SM-840 Class 2.
I've emailed pictures to Steve, should be hosted soon at
http://www.stevezeva.homestead.com/
Sorry for the rambling, but I guess I can boil the questions down to:
1. Is it acceptable (per above specs and class level) for there to be
solder adhered on top of traces that are (by design) covered by soldermask?
2. The metalization in the areas of mask not on conductors certainly
appears to be solder, although the last batch I sent back they thought it
was burnished mask. My in house analysis is limited to a microscope that
can zoom to 40X, but that's about it.
Any suggestions would be welcome.
Thanks,
Hal
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