Laser beam soldering: an attractive alternative to conventional soldering technologies

Laser beam soldering (LBS) is a non-standard manufacturing process for electronic packaging and interconnection technology today. Due to the actual trend towards complex and cost intensive products, LBS gains more attention for certain applications in this field. For mass production in automotive applications a fully automated and temperature controlled LBS process was developed. The achieved results are discussed with respect to quality, reliability and process efficiency and compared to established micro flame (hydrogen) soldering technology. The development of the LBS process is presented. The process window is optimized using High Speed Video Imaging. Temperature signals are logged by means of pyrometry. The processed parts are evaluated with metallographical assessment of solder joint quality. Especially cross sections reveal the fine grained structure and the shape of the meniscus of the solder joints. The reliability is proven using shear strength tests and thermally induced strain cycles. Conclusively, LBS is a stable, reproducible process for applications requiring controlled and locally restricted heat input. The thermal and mechanical stress is reduced in comparison to conventional techniques