Pressureless Sintering Performance Enhancement of Ag Pastes by Modification of Ag Nanoparticles with n-octylamine

Wide band semiconductor materials represented with SiC and GaN are widely employed in power modules due to their high electrical and thermal conductivity, high operating voltage, high operating temperature and low switching losses. The operating temperature of power modules can even exceed 250 °C, which places higher demands on device packaging and interconnects. Traditional interconnect solutions, such as lead-free solder and transient liquid phase technology, can no longer meet the demand of high temperature applications. Ag sintered technology has attracted widespread attention in the electronics industry due to its excellent electrical and thermal conductivity. In this paper, we propose a method for surface modification of commercial Ag nanoparticles with n-octylamine (NOA) to prevent agglomeration at room temperature for enhanced pressureless sintering performance. The influence of NOA content on shear strength, sintered morphology and fracture surface morphology were explored. A modified Ag nanoparticle with 69.3 MPa shear strength was measured for 60 minutes at 250 °C in air. The results of EDS analysis revealed that the surface of Ag nanoparticles formed a coating after the adsorption of NOA molecules. Moreover, this paper describes a mechanism of NOA modification of Ag nanoparticles to improve sintering performance, which provides sufficient experimental evidence and theoretical support for its practical application of pressureless sintering technology.