Effect of oxygen on Ag sintering technology with low temperature pressureless

Ag sintering technology has received more and more attention to achieve the high-temperature applications above 250°C due to its super physical properties in the wide band gap power device modules. However, the sintering mechanism of micron-size Ag particles during the sintering process was not clear especially at low temperature and pressureless. In this paper, the hybrid Ag paste was used to achieve low temperature pressureless sintering. The Ag paste was sintered in air and nitrogen atmosphere in order to investigate the effect of oxygen on sintering. Mechanical properties including tensile fracture strength and shear fracture strength were evaluated for sintered Ag specimens under the two kinds of sintering conditions by tensile test and shear test, respectively. These results show that both of tensile strength and shear strength of specimens sintered in air was far larger than that sintered in nitrogen. In addition, the mechanical properties of sintered Ag related to the microstructure are discussed based on SEM and TEM observation. These results revealed that O₂ play important roles in sintering, which promote Ag nanoparticles self-generation and thus strengthens connection among Ag particles.