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March 2000

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Subject:
From:
Julie Dixon <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 22 Mar 2000 14:38:29 EST
Content-Type:
text/plain
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Dear Net,

1. Is there a name, we use smut, for the slimy, dark brown-black deposit in
low
current density areas on panels in acid copper plating? It wipes off as a goo
down
to the foil copper.
2. Is it related to DML boards only? Palladium on surface issue?
Or is it related to DML's reaction with the brightner system in the plating
bath?
I've been told it's brightner related, but it never occurs on anything not
DML'd.

 -Cold panels 70 F almost always manifest it.
 - But recently we saw it on 74 F panels plated at 35 asf for the first 5
minutes.
   a. bath had been inactive for 5 days, but continuously filtered, and air
agitation
       had been on for 2 hours prior to plate. Anode film?
   b. design was a horrendous mismatch of copper area. We panelized best we
could
        front side-   1-9"         9-18"     the front 1-9" area smutted.
Other area were ok.
                         10x            1x
                         copper area
        back side-   1-9"         9-18"
                           1x           10x

Any experience with this? We thought we'd shelved this prob. with 98 F rinses
in the
pre plate. Sulfuric dip and plating bath are at the mercy of ambient
conditions, typic
74 F.

Thanks,
Julie

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