A new line of Pb-free no-clean solder pastes was introduced by the Contact Materials Division (CMD) of Heraeus during Apex last week. The F640 Series is said to promote wetting and minimize defects with tin/silver/copper alloy soldering. 
 

With a wide process window, the paste is able to compensate for process variations in printing, component placement and soldering. Provide wetting on a variety of surfaces and finishes, and leave behind a clear residue. Offer minimal slumping and exceptional print-to-print consistency, can also be reflowed in air or nitrogen environments.