In a message dated 10/9/02 12:51:56 PM Pacific Daylight Time,
[log in to unmask] writes:

<< How should I, or better yet how do you, understand the phrase "copper
distribution"?
  >>

Printed Circuit Boards are electroplated with Copper to give conductivity in
the holes.  Along the way, they are plated on the surface as well.  This
electroplating is not uniform, and as the holes get smaller, and deeper, and
the lines on the have a non-uniform distribution on the surface, the plating
becomes less uniform.

The rule is that thou shalt have 1 mil of copper (minimum) in the center of
the holes, the amount of Copper on other parts of the board will vary, but
will always be more than the amount in the center of the hole.

Hope this helps.

Rudy Sedlak
RD Chemical Company

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