Never use Immersion Tin on second side reflow. The process is very
suspect(copper migration). It works great though for one pass.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Larry K
Sent: Tuesday, July 17, 2007 3:35 PM
To: [log in to unmask]
Subject: [TN] Immersion Tin

We are having problems with solderability of the PCB on oursecond side
reflow. Everything looks good after reflowon the first side but when we run
the second side we have non-wetting of the pads of this side. 
   
  Just to ensure we were doing everything correctly,we switched sides (we
did the second side first and then did the first side as a second reflow)
and the problem was still after the second reflow. We are thinking this
validated our process because the side causing us problems switched with our
experiment. As I said in the suject line, this is Immersion Tin. Any
suggestions for a cure?
  thanks,
  Larry

 
---------------------------------
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