Reliability And Verification Of Lead - Free Soldering Process For Automotive Electronic Control Products

Although the relevant laws and regulations, such as the End of life vehicle(ELV), Waste electrical and electronic equipment(WEEE), Restriction of the use of Hazardous substances in E/E-Equipment(RoHS) as well as China’s electronic products pollution control management methods has become effective, but the cars are still in the exemption periods. In order to improve the environmental requirements of the automotive products, the world’s leading automobile manufacturers such as Volkswagen, General Motors, Ford Motor has start to reduce the harmful substances(lead) for automotive electronics products, and transfer reflow soldering process from lead solder paste to lead-free solder paste.Currently, there are lots of research works for the development process of lead-free solder paste, but under the consideration of high requirement for the reliability, most of the automotive electronic control products still are lead soldering process. This paper is design to verify the reliability of automotive airbag control unit from lead soldering process to lead-free process. Under the condition of no change for the production line equipment and tooling, by use of lead-free solder paste(Alpha OM335type, Sn96.5Ag3.0Cu0.5) to produce the test samples to inspection and validate its reliability, meet the IPC standard as well as automotive industry standards to achieve the lead-free soldering process. After completed and passed above reliability validation test, which the results have proved as the technical data to support for mass production of lead-free soldering process.Firstly, analysis the impact factors, parameters for the solder joint reliability after used the selected solder paste and lead-free soldering process, then design6groups of validation methods under different conditions. The inspections methods includes solder joints visual inspection, push-pull test, cross section test, whisker test, ionic contamination test, high/low temperature test, thermal shock and vibration test to validate the reliability.This paper also discusses the requirements for high reliability requirements of automotive electronic control products as well as the inspection methods. The validation methods, solder paste bran used in this paper can be taken as an important direction in lead-free soldering process of automotive electronics products.