The development of 3D integrated circuit (3D IC) and thin wafer have been introduced to the industry, and the electronic packaging is facing new challenges in the fabrication processes. This proposal is looking for new low temperature solder alloys to meet the requirement for the bio-compatible devices and the advanced packaging technique. The temperature will be in the range between 50oC to 100oC. The warpage of the thin wafer will be minimize in such a low temperature. The high-Sn content solder would be replaced by high-In and Bi with the addition of Sn or Ga. The first year will focus on the composition and the corresponding thermal properties of the alloys. The low temperature solders will react with Cu or Ni substrates to study the interfacial reactions. The second year will investigate the microstructure and the mean-time-to-failure behaviors of the solders under current. The solid-liquid interdiffusion bonding technique will be conducted in the last year to fabricate flip chip with low temperature microbumps. The chips will be scanned by synchrotron radiation X-ray to investigate the effect of solders on the warpage. The results of the project definitely can bring essential knowledge for both the academic and industry.