To alleviate concerns of manufacturing cost and efficiency of solar cell fabrication, a belt type-high temperature furnace with three temperature zones is employed in order to increase the solar cell manufacturing throughput. In addition, characterization of the firing process for the contact formation is investigated to achieve the most efficient solar cell device fabricated. Statistical design of experiment (DOE) is used in order to perform a set of firing experiments in a systematic way. Response surface models for the efficiency are established for the characterization of multivariate problem. Furthermore, the optimized process recipe that can provide 15.9% of efficiency is proposed through the process optimization.