Bob,

My two cents for the Friday - If I read the question correctly, you are
asking about adhering either a 0.1um tin plated part, or a 2um tin plated
part to bare, non-metallized FR-4.

Given that the tin plated components are virgin/not oxidized, it is my
belief that the adhesive will adhere much better to the bare FR-4 than to
either of the tin plated components.  In the virgin state, I would not
expect much, if any difference between them.

Should the Sn plated components have been subjected to a thermal exposure of
some kind - what was formerly beneath the thin Sn plating may now also be
oxidized and corrupting the surface making it's interface weaker sooner.

Heat cure adhesive, UV, or room temp? - I am not a great fan of adhesively
bonding [long term] to Sn.  The higher the heat cure, likely the worse it
will get.



Will see how much other traffic this starts  :-)

Steve



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of bob wettermann
Sent: Thursday, April 09, 2009 11:17 AM
To: [log in to unmask]
Subject: [TN] Friday Theorizing

Dear Technetters:

Has anyone done any adhesion testing of a 2um tin-electrocoated surface
(copper carrier) to FR-4? How about a 0.100um tin electrocoated surface? Can
someone theorize on which might give better adhesion using a 2-part epoxy?

Regards

 Bob Wettermann
BEST
PH 847-767-5745

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