Available thermal budget in lead-free reflow process

The electronics industry will have to implement lead-free soldering in the near future. Lead-free technology implementation phases are divided into lead-free processes and leadfree product. The prime issue is the component availability and component heat tolerance with the higher soldering temperatures. There is concern about the stability and heat resistance of a range of plastic encapsulated devices, capacitors, filters, connectors and even printed circuit boards. In this study the process window size of the lead-free soldering process is compared for the current tin-lead process. Parameters affecting the soldering process, e.g. the temperature difference between a component´s top and bottom surface during the soldering, are discussed. Optimization of the reflow oven for lead-free technology is also discussed. Experiments are presented showing in some cases more variation in the normal reflow oven capability than what is the measured temperature difference between the top and bottom surfaces of the component, clearly highlighting the complexity of the problem in practice.