Roy,

Back in 1995 at a different company, I worked on a multilayer RF
amplifier board that mounted on an aluminum surface. We used a different
drill code (+1mil) for the non ground vias and specified that drill code
in the NC drill file as the locator for the controlled depth drilling.
Since that time I've heard the product has performed well in the field
with no problems. Can't remember where we got it fabricated but I
remember calling several vendors to find one with that capability. Just
a thought on the pad removal. You may need the bottom pad for the via
hole plating process. Just use a small pad on the bottom layer and let
them drill it out.

Best Regards,
Gary Shoemaker, C.I.D.
Senior PCB Designer

Cisco Systems, Inc.
3875 Embassy Parkway
Akron, Ohio 44334

Phone: 330-664-7927
Fax: 330-664-7301

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