I have a 2 layer board where one side is to be a thermally conductive.  It
is a poured copper plane with its only connection being to the mounting
holes where copper straps will be part of how it gets mounted.  We call
these cold stations.  Usually connectors are mounted on both sides of the
board.  It is basically to move signals from inside a cryo instrument out
to the world.  We have done these with a HASL finish in the past but know
we can get better thermal conduction if we can leave off the tin/lead
finish and just have the bare copper.  The holes need to be plated, no
solder mask or silk screen is applied.




My questions:
Is there any thing special instructions I should do on the fabrication
drawing besides remove the finish, solder mask and silk screen
instructions? The finish I want is the copper any special statements to
accomplish this?

Besides the oxidation problem do any other problems come to mind that I
should be concerned with on a board that will have the copper exposed in
this manner?

Thanks for you input and time!


Dee Stover  [log in to unmask]
Associate Technician Design
National Optical Astronomy Observatory
950 N Cherry Ave
Tucson, AZ 85719
www.noao.edu

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