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August 2003

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Subject:
From:
Tony Steinke <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Mon, 18 Aug 2003 14:48:05 -0400
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text/plain
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text/plain (83 lines)
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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