Study on conductive paste of silver particles for power semiconductor devices package

Abstract

Sintered silver has been used as an interconnect material for power electronic components in recent years. In the early days of development, micron-sized Ag particles were used for the silver conductive paste, however, high temperature and high pressures of up to 40 MPa were needed to achieve high performance sintered joints, which may damage the electrical component.Therefore,low pressure sintering using Ag nanoparticles has received great interest. In our work, we evaluated the properties of the silver nanoparticle conductive paste as a low-temperature, low-pressure interconnect material. Shear strength test showed that the silver paste with 60%wt Ag loading sintered under 10MPa for 20 min can achieve the best result among 10min, 20min, 30min and 40min.Moreover, as the sintering pressure increases, Cu-Cu joints clearly increased. Silver content is also an important factor affecting the shear strength. When we increase the silver loading from 60%wt to 80%wt, shear strength increases simultaneous. Shear test results show that a high shear strength of 57MPa can be achieved for the 80wt% Ag loading under 10MP at 300° C. which indicates that our silver nanoparticle conductive paste has excellent mechanical properties.