SOLDER POWDER CHARACTERISTICS AND THEIR EFFECT ON FINE PITCH PRINTING OF SOLDER PASTE

摘要

The continuing demand for smaller and lighter electronic products has driven the use of miniature PCBs as well as miniature components. The assembly of miniature components requires fine solder joints; and, finer solder joints require advanced solder paste with finer particle sizes. The paper presents recent results of a project on understanding key characteristics of lead-free powders for solder paste applications. The influence of the powder characteristics such as particle size distribution and oxygen content on the solder paste properties is reviewed. The oxide layer formed at the powder surface is characterized using electron microscopy techniques including Auger Electron Spectroscopy (AES) and Transmission Electron Microscopy (TEM). The effects of powder characteristics on the viscosity and stability of solder pastes are discussed.