Hal,
What it looks like to me is scratches from the hot air solder knife blades
when exiting the HASL machine,
which probably is conductive.
Do the marks have a "pattern" to them?(same direction)
Tony Steinke
AIT-Atlanta Inc.
----- Original Message -----
From: "Hal Winslow" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, August 18, 2003 2:08 PM
Subject: [TN] Is HASL adhered to conductors acceptable?
> 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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