August 7, 2007

Many component manufacturers because of RoHS regulations have changed their 
component lead finish to a pure matte tin finish.  Most of these folks have 
also implemented some form of tin whisker mitigation (anneal after plating, 
use a nickel flash, etc.).

It is my understanding that assembly level soldering of these component 
leads using the traditional Sn63Pb37 solders for wave soldering, or reflow 
soldering using Sn63 based paste, with traditional RMA or Rosin based L0/L1 
flux does not need to change the wave or reflow soldering profile 
temperatures since the matte tin plated component leads are considered 
solderable as a "drop-in" replacement for SnPb plated component leads.

Can folks confirm the above conclusion or otherwise provide comments?  Is 
there any technical information on soldering to matte tin plated leads using 
Sn63 solder alloy at assembly?  Will the same intermetallics form as when 
soldered to traditional Pb-bearing leads with Sn63 solder and FR4 board 
material?

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