Hi Bob,

Faraday's Law says that the weight (i.e. thickness at the same density) of
electrodeposited metal is directly proportional to the quantity of electricity
passed, i.e. current x time.  Therefore, if say your calculated current density
is 30 ASF and plating time is calculated for 1 mil thickness, but you are
getting only 0.5 mil in the center of the hole -- your current density there is
15 ASF (provided your current efficiency is 100% -- a pretty close approximation
for acid copper low current density plating).  Can't argue with Faraday.

Eric Yakobson
Alpha PC Fab




Robert Jordan <[log in to unmask]> on 10/19/99 07:45:43 AM

To:   [log in to unmask]
cc:
Subject:  [TN] ASF info...Super Plater




Hello,
Once again another question drawing in the vast talent and experience of
Technet. Is there a way to calculate the ASF inside a through hole in a
printed circuit board during the electroplate copper process? Is that ASF
different if the pth is in the middle of a ground plane vs. an isolated
area? If no formula exists please bend my ear with your opinion.

Thanks,
Bob Jordan

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