At 02:04 PM 9/1/01 -0400, Mike Reagan wrote:
>I doubt if you will  find a decent board house that is willing to fabricate
>poygon pours on internal layers.....notice I said "decent"  Talk to some
>manufacturing engineers to find out why this is frowned upon

I suspect that this is overstated. Fabricators may not want to produce 
copper-heavy layers that are asymmetrical in the stackup, because of 
potential warping.

But using a copper pour in lieu of a negative plane (presumably balanced by 
another copper-heavy layer should not be any additional problem, especially 
if dead pad removal is used with the photoplot.

By the way, I'd really like to know more about the warping allegedly 
produced by asymmetry. Has anyone actually seen this and verified that the 
asymmetry was the problem? I have a little trouble imagining a few mils of 
very ductile copper having enough strength to move the fiberglass around.

[EMAIL PROTECTED]
Abdulrahman Lomax
Easthampton, Massachusetts USA

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