Pradeep,

Lower plating density is more susceptible to voltage potential variations and space charge effects which reduce the uniformity of the ionic space charge field by allowing micro charge flows around the feature being plated...


Paul 

Paul Edwards
Surface Art Engineering


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Pradeep Menon
Sent: Friday, October 22, 2010 7:41 AM
To: [log in to unmask]
Subject: [TN] plating projections

Dear technetters,

Iam referring an observation that we have in our PCB fab line. We observe
some small growth like projections on copper pads / tracks after copper
plating. These boards are plated with lower current density and for a
longer time. The same boards in the same chemical baths were plated with
higher current density for a shorter time wherein we do not observe this
at all. We had filtered the complete bath solution in the plating cell and
also cleaned up the anode bags etc.

We are not able to understand whether there is any difference when we
plate with a higher current density which avoids such growth like
projections.

Anybody can give some inputs in this

Regards

pradeep


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