In RoHS compliance of electronics circuit board design and manufacturing, Lead-free solder alloys typically have melting points that are 30-40°C higher than the melting point of lead alloys. While using the lead-free solder alloys, we have to apply higher temperatures in soldering, which affect reliability of components, PCB, and solder joints.

High Temperature Issues of Lead-Free Solders

Higher melting point of lead-free solder affects reliability of electronic equipment manufacturing through a variety of issues such as:

  • Thermal fatigue of solder joints
  • Delamination of multi-layer PCBs
  • Popcorn failures of IC packages
  • Degradation/Damage to heat sensitive components

Guidelines to Avoid High Temperature Effects of Lead-Free Solders

To mitigate the reliability risk of degradation/damage of components during soldering with higher-temperature (or higher melting point) lead-free soldering materials, the following precautions are to be taken.

  • Never exceed the soldering temperature limits specified in component datasheet
  • Select a suitable lead-free solder alloy with melting point that does not harm heat sensitive components
  • “Max. soldering Temp. allowed for components” is greater than “Melting
    point of solder alloy” is greater than “Maximum operating Temp. of board”.
  • Select components with ability to resist thermal stress
  • Select component packages with lower thermal resistance