Hot air solder leveling, in the era of tin-lead solder, was the surface treatment method with the highest usage rate in the PCB industry in Taiwan because it had a certain level of competitiveness. With its well-developed technique, low production cost and rapid production process, it was widely used for over 20 years. However, with the consideration of environmental protection during recent years, the solder can’t be used anymore.
The melting point of lead-free solder is 30 °C higher than the conventional tin-lead solder on average; to adapt to the new high temperature process, adjustments to the equipment and techniques must be made. However, we believe that even in the future, lead-free solder will continuously be the most competitive surface treatment method.