been-der, dun-dat.
This is difficult but not impossible.
The trick for us (after many long hours) was just a touch o' cleaner to the
post-rout wash-off rinse.  We used RBP "Rinse Aid 90" (mild chelate, if
memory serves...) at <5% b.v. with marked improvement in adhesion of
Probimer 52 & 65 over reflowed Sn/Pb.
Good luck.

J. Felts

-----Original Message-----
From:   Terrie Balck [SMTP:[log in to unmask]]
Sent:   Monday, November 09, 1998 1:52 PM
To:     [log in to unmask]
Subject:        [TN] Soldermask adhesion over tin/lead

I am wondering if anyone has had any recent problems with LPI soldermask
adhesion over reflowed tin/lead. I realize that IPC-SM-840 says that there
are adhesion problems but still gives guidelines for adhesion for types T
and H that we are not adhering to (ie more that 10% of soldermask coming
off on tin/lead traces, after reflow). We are using Morton Epic 200. We
have studied our cleaning and surface prep as well as our curing
times/temps and we cannot seen to find anything that we are doing that is
different. Any info/comments would be appreciated.
Terrie Black
QA Mgr. CSI

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