Microstructure and Mechanical Properties of Type 8 Solder Paste for Mini-LED Assembly Using Laser-Assisted Bonding

In response to the ongoing miniaturization and high-density requirements of the latest electronics industry, the size of semiconductor components is significantly decreasing. As the current semiconductor front-end processes have reached their limits in miniaturization, there is a need for further miniaturization in the back-end processes. In the back-end processes, solder, primarily used to connect chips and PCBs, is also undergoing miniaturization, with solder in paste form gaining attention. In this paper, 8-type solder paste with a powder size of 2-8μm was applied to a PCB using stencil printing, followed by the mounting of mini-LEDs and bonding using laser-assisted bonding. Subsequently, aging experiments were conducted to evaluate high-temperature reliability. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were employed for microstructure analysis, and shear tests were conducted to assess shear strength and solder adhesion.