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Re: gEDA-user: General ground/power plane design questions

At 19:45 -0700 20-10-2004, Daniel Wisehart wrote:

On Wednesday 20 October 2004 12:21 pm, Karel Kulhavy wrote:

 On Wed, Oct 20, 2004 at 09:07:48AM -0700, Steve Meier wrote:
 > Second, the power and ground planes should be inner layers. But for your
 > frequencies I don't think you wil see many issues.

 Why?

Why should power and ground planes be inner layers?  Because the board maker
has a problem keeping a whole plane of copper attached to an outer layer.  As
it heats and cools, it keeps trying to curl up and pull off of the board.  On
an inner layer it is going to stay put.
Why ?

The board houses I have worked with create multilayers by (warning: oversimplified) laminating together sandwiches of multiple two-layers. Why would these have different heat issues than outer layers ? The only issue I know with lots of copper on outer layers is that outers are usually electroplated to increase copper thickness; I've encountered one single low end in-house board manufacturer which couldn't zap enough current through the electroplating machine to handle large areas.

Solder resist will (by design) stick fine to copper, and silkscreen works great over solder resist. Besides, some board houses will silkscreen over reflowed solder/tin.

Please let me know if I'm missing anything.

JDB
[looking at double sided / multilayer PCBs done at several different board houses in .nl, .uk and .ca; all with large solid planes on outers, none with any signs of peeling/delamination]
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