Experiments on the effect of sintering pressure on the creep response of sintered silver material

Purpose This work aims to investigate the influence of sintering pressure on the creep deformations of sintered silver specimens. Design/methodology/approach Test specimens are fabricated through the stencil printing of microsized silver paste, sintered at 230°C sintering temperature for 5 min. Three sintering pressures, including 15, 20 and 25 MPa are considered. Comprehensive creep tests are conducted at room temperature, and deformations are measured using advanced optical digital image correlation techniques. Findings The results have indicated that sintering pressure significantly influences the creep behavior of sintered silver, with higher pressures yielding samples of superior quality and increased creep resistance due to reduced void density. A power law-based creep constitutive equation is developed in this paper to incorporate the impact of sintering pressure on the steady-state creep rate, and its validity has been carefully evaluated. The findings suggest that using higher sintering pressures in the assembly of power electronic modules with sintered silver interconnects can enhance their strength and reliability. Originality/value Sintered silver bonds are one favorite option in power modules due to their excellent electrical, thermal and mechanical characteristics. The sintering process is generally controlled by the sintering temperature, the sintering pressure and the process duration. The sintering layer strength, mechanical properties and reliability are, in fact, highly influenced by the sintering process parameters, such as the sintering pressure. Therefore, the results of this work can be invaluable for designing power devices with sintered Ag bonds.