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Wed, 22 Mar 2000 16:21:57 -0700 |
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We saw this recently and traced it back to a nylon smear from the
deburring brushes that were not dressed properly. Hope this helps.
Rick Howieson
GTC
>-----Original Message-----
>From: Julie Dixon [SMTP:[log in to unmask]]
>Sent: Wednesday, March 22, 2000 12:38 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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