Study on the Performance of Laser Ball Soldering for Three-Dimensional Stacking of Radio Frequency Microsystems

This paper evaluates the reliability of laser ball soldering under different materials (silicon, ceramics, PCB), different solders (lead-free SAC305, leaded SnPb6337), and various sizes of solder balls (200, 350, and 450 μm) through the application design experiment method. The welding process parameters are systematically optimized by ball coplanarity, solder ball shear strength, and intermetallic compound alloy layer thickness. We obtained a large amount of reference experimental data and confirmed the innovation and practicality of laser ball soldering technology. The quality of the solder balls obtained using the laser soldering process can meet the technical requirements of the 3D stacked vertical interconnection of the radio frequency microsystem.