I'm working on a board that I would want to have professionally made
after I do some hand etched prototypes.  For the professionally made
version, I'm looking at a DFN package amp to save on board space, and
I dont have any DFN footprints in eagle that I know of already.  (I
have the default eagle 5.7 libraries, and sparkfun's library)   I'm
putting together a footprint for a a 3x3 DFN 8 lead package from
linear.  http://cds.linear.com/docs/Packaging/DFN_8_05-08-1698.pdf
They dont specify solder mask defined or NSMD pads.
In eagle, when I add pads, it defaults to NSMD pads, and the gap
between the the 2 mask opening is very very thin, and probably wouldnt
come out well.  Ive seen places online suggesting that on .4mm pitch
stuff, the opening usually just turns into one big opening.  Is there
a way to reduce the solder mask opening in eagle so that there is a
bar of solder mask between the pins of 0.5mm pitch leads? or should I
leave it be?  Change to SMD pads?  Ive read in an intersil document
that NSMD is preferred for the perimeter pads, and if possible for the
center heat pad.  http://www.intersil.com/data/tb/TB389.pdf

If I'm making mask defined pads in the future I assume I'll have to
uncheck the mask checkbox in eagle, and go back and add in my desired
pad opening in manually?

Ive hand soldered some TSSOP stuff by hand, but they were on boards
not designed by me, and I cant remember if there was a mask between
pads or not.  I'm pretty sure there was, as I was drag soldering with
a "gull wing" tip without issue.

Thanks,
--=20
Jonathan Hallameyer
--=20
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