John..
I'm still surprised! We have been designing 12-14 layer (standard)
smt designs for about a zillion years, maybe not quite a zillion, but
a looonnng time and no vendor has ever requested that the inner layer
pads be larger. In fact, unless I am looking at the formula/chart in
the Mil and IPC specs incorrectly, the minimum annular ring requirement
for internal is .001/.002 mils vs .002/.004 mils for external layers.
Therefore, by definition, your external pads should be larger. What
am I missing???
Regards,
Bob