1. Smut is a good term.
2. In past life, have had to run DM real quick or micro-etch the p---sss out
of it. Watch your hold times.
3. Never let an acid copper bath set for over 24 hours without at least a
minimal low current dummy to start the bath up with.  I don't know about the
e voodoo anode film but you can watch this smut being created in the first
few seconds of a hull cell test and compare it to dummied Vs non-dummied and
correlate to current density all at the same time.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Julie Dixon
Sent: Wednesday, March 22, 2000 2:38 PM
To: [log in to unmask]
Subject: [TN] Low Current Density Smut


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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