Good afternoon.

Two questions:

1) Is "negative etchback" typical for multilayer board fabrication these days, 
or is the "good" kind still available?

2) With a .002" minimum internal annular ring requirement (MIL-P-55110), and a 
.040" diameter internal pad, what is the maximum drill size that can be used 
for an 8-layer Polyimide board .062" thick?

OK., three questions:

3) Would the drill size differ for negative etchback than for a positive 
etchback condition?

Thanks for the info...

Jim Marsico
(516) 595-5879
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