What are the main soldering defects associated with lead-free reflow soldering?
Lead-free can increase the incidence of solder defects and requires a good understanding of the properties of the lead-free alloy and flux system to prevent them. Defects such as bridging, non-wetting, de-wetting and the potential for solder balls can increase. Choosing the correct flux chemistry compatible with the metals to be soldered, and having an optimized reflow profile will prevent the increase in defects. Insuring the solderability of the boards and components by proper storage and handling methods will also enable good soldering with lead-free pastes. If the chemistry is chosen carefully and the SMT process controlled the results in yields will be the same as the Sn63 process.
