Exploring porosity effects of on mechanical behavior of sintered nanosilver for double-sided cooling packaging of high-power devices: a multiscale modeling

Purpose-The purpose of this paper is to analyze and compare the mechanical properties of sintered nanosilver with different porosities atboth the mesoscopic and macroscopic scales and to conduct a multiscale analysis of the porosity effect on the mechanical properties ofsintered nanosilver. Design/methodology/approach-This paper establishes a mesoscopic model for the uniaxial tension of sintered nanosilver and amacroscopic model for chips containing sintered silver layers. Using thefinite element method, combined with crystal plasticity theory andunified creep plasticity theory, a multiscale analysis is conducted for the mechanical properties of sintered nanosilver. First, stressdistribution characteristics under uniaxial tensile loading for different porosities in sintered nanosilver polycrystal models are analyzed atthe mesoscopic scale. Second, at the macroscopic scale, the mechanical performance of sintered nanosilver layers with varying porosities inhigh-power chip models under cyclic loading is analyzed. Finally, the porosity influence on the damage evolution in sintered nanosilver issummarized, and simulations are conducted to explore the evolution of damage parameters in sintered nanosilver under differentporosities. Findings-In the mesoscopic model, the presence of mesoscale voids affects the stress distribution in sintered nanosilver subjected to tensileloading. Sintered nanosilver with lower porosity exhibits higher tensile strength. In the macroscopic model, sintered nanosilver layers with lowerporosity correspond to a more uniform stress distribution, whereas higher porosity leads to faster accumulation of plastic strain in the sintered layer.During chip packaging processes, improving processes to reduce the porosity of sintered layers can delay the initiation of damage and thepropagation of cracks in sintered nanosilver. Practical implications-During chip packaging processes, improving processes to reduce the porosity of sintered layers can delay the initiation ofdamage and the propagation of cracks in sintered nanosilver. Originality/value-This paper innovatively uses a mesoscopic crystal plasticity constitutive model and a macroscopic unified creep plasticityconstitutive model to analyze the mechanical behavior of sintered nanosilver with different porosities. It comprehensively investigates and explainsthe influence of porosity on the mechanical performance of sintered nanosilver across multiple scales.