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October 2000

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Subject:
From:
"Stephen R. Gregory" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Fri, 6 Oct 2000 16:29:08 EDT
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In a message dated 10/06/2000 11:56:36 AM Central Daylight Time,
[log in to unmask] writes:

>  would rule out air saturation in the tank since the pits were only on one
>  side of the board.  And I would probably rule out etch-resist breakdown,
>  since that is normally not circumferential.  But to be certain about the
>  etch-resist, I would X-section a pit and see how deep it goes.  My guess is
>  that it starts at the base laminate.  If it's an etch-resist problem the
>  pit will not be as deep.  Maybe only half way through the plated copper.  A
>  base laminate starting point indicates an obstruction to copper plating;
>  gas, residues, air pockets.
>
>  Mark Mazzoli

Hi Everybody!

If you go back to:

http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures

I did what Franklin Asbell suggested. I took one of the boards and using an
exacto knife, carefully scaped things away to see how deep things went...and
I took a series of pictures as I went...

pitscrape.jpg - Starts off just getting into the trace with all the solder
mask off.

pitscrape2.jpg - Is about 1/3 the way into the trace, and the pit into the
middle is  getting smaller, which tells me I'm starting to get to the bottom
of that one.

pitscrape3.jpg - Is about 2/3 into the trace and the middle pit has almost
disappeared, and the other two are starting to bottom-out as well.

pitscrape4.jpg - Shows that I was able to keep scraping and removed the pits
in the traces...trouble is, there's not much copper left in the trace beneath
the pits...

Just thought ya'll might want see how deep things got...and from the
explanations I got from everybody, I'm still somewhat confused...some say
that if the pit doesn't go all the way down to the laminate then is was a
etch resist problem, but then others have said that if they don't go all the
way down, it's from bubbles attaching to the traces during plating...or have
I just confused myself?

Thanks again!!

-Steve Gregory-

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