The effect of different metal pad sizes on shear stress in solder ball bonding

Abstract The reliability and performance of solder ball joints are critical factors affecting the durability and functionality of electronic parts. This study investigates the relationship between metal pad size and the bonding force of solder ball joints. Mechanical strength tests were performed on solder ball bonds with various pad diameters and heights to evaluate the shear stress. Results showed that there is a direct correlation between pad size and bonding stress, with larger pad sizes increasing the contact area and forming a larger area of intermetallic compounds during reflow soldering, resulting in improved mechanical robustness. Conversely, smaller pad sizes were found to be more susceptible to mechanical failure and crack propagation under stress and exhibited higher solder ball dropout rates and misalignment. This study provides valuable insights for optimizing pad design in microelectronic packaging to improve the mechanical reliability of solder ball bonding in applications. Furthermore, it also highlights the importance of considering pad size as a critical parameter in the design and manufacturing process of electronic components.