Effect of Phosphorus Content on the Interfacial Microstructure and Mechanical Properties of the Solder Joints

• Main Authors: Ting-Chun Yeh, 葉庭均
• Other Authors: Cheng-En Ho
• Format: Others
• Language: en_US
• Online Access: http://ndltd.ncl.edu.tw/handle/m226u2

碩士 === 元智大學 === 化學工程與材料科學學系 === 103 === Recently, replacement of electroless nickel/electroless palladium/immersion gold (i.e., Ni-P/Pd-P/Au, ENEPIG) surface finish by the Pd(P)/Au dual layer (EPIG) on the Cu pads is being considered and adopted by the electronics industry. This is because the presence of a Ni(P) deposit can degrade signal delivery performance in radio frequency devices, and a thick Ni(P) film (> 5 μm) can hinder the development of fine-pitch packaging. As the alternative, several types of viable surface finishes are suitable for soldering reaction. Very recently, EPIG was one of the surface finishes that have received significant attention in the electronic industry. However, the data regarding the P effect in EPIG system are still lacking in the literature. The first part of this thesis is systematically conducted to investigate the effects of P content between Au/Pd/Cu and Au/Pd(P)/Cu multilayers in soldering application. The second part of this thesis aims to uncover the effect of minor P addition. Although P content from surface finish layer was not found to influence the interfacial microstructure or mechanical properties directly, the P content was found to dissolve in to solder region resulting in P contained phase formed near the solder/substrate interface. Dissolution of metallization pads into solder (e.g. Cu or Ni) plays a significant role in determining the overall reliability of solder joints. However, regardless of varied surface finish deposition, the effect of P dissolute behavior induced conversions of microstructure and mechanical properties were still not well established. The correlation between the interfacial microstructures and mechanical properties of the solder joints with various P concentrate values was established in this study.