Kester

As lead-free gains momentum, many engineers are striving to set-up a wave solder process that maintains production yields but also offer reliable assemblies. Much has been written on these topics in the past 5 years. Less confusion does exist today about alloy choices available to replace leaded solders, however many are struggling with their successful implementation. Once the lead-free alloy is selected, a solid understanding of its chemical and physical properties is required to enable reliable soldering.

This paper will discuss commonly experienced defects associated with NoClean surface mount processes and propose methods to solve these issues. Much of the discussion can be applied to any surface mount process (i.e. water soluble, RMA, or No-Clean), but some are directly associated with No-Clean processes.

Driven by environmental and health concerns, the RoHS legislation has mandated the electronic assembly industry to transition from eutectic tin-lead to lead-free soldering, which carries forward a revolution in the formulation of soldering materials.