The Impacts of Laser and Reflow Soldering on Solder Joints

With the advent of the "post-Moore era", heterogeneous integration based on small chips will become the mainstream of semiconductor packaging. Small chips tend to be packaged in 3D directions to achieve flexible modular integration and system-on-chip integration. It should be considered that 3D packaging will bring some problems. For example, high-power electronic components often dissipate large amounts of heat during use, which requires a high melting point solder to maintain the thermal stability of the interconnect. However, the interconnection of some heat-sensitive components requires low-temperature solder. Some of these substrates have high heat sensitivity and cannot withstand high temperatures and prolonged heating in reflow ovens. Laser soldering can be used as an alternative soldering process due to its localized and non-contact heating, rapid temperature changes, and no need for flux.