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 at both the mesoscopic and macroscopic scales and to conduct a multiscale analysis of the porosity effect on the mechanical properties of sintered nanosilver. Design/methodology/approach: This paper establishes a mesoscopic model for the uniaxial tension of sintered nanosilver and a macroscopic model for chips containing sintered silver layers. Using the finite element method, combined with crystal plasticity theory and unified creep plasticity theory, a multiscale analysis is conducted for the mechanical properties of sintered nanosilver. First, stress distribution characteristics under uniaxial tensile loading for different porosities in sintered nanosilver polycrystal models are analyzed at the mesoscopic scale. Second, at the macroscopic scale, the mechanical performance of sintered nanosilver layers with varying porosities in high-power chip models under cyclic loading is analyzed. Finally, the porosity influence on the damage evolution in sintered nanosilver is summarized, and simulations are conducted to explore the evolution of damage parameters in sintered nanosilver under different porosities. Findings: In the mesoscopic model, the presence of mesoscale voids affects the stress distribution in sintered nanosilver subjected to tensile loading. Sintered nanosilver with lower porosity exhibits higher tensile strength. In the macroscopic model, sintered nanosilver layers with lower porosity 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 the propagation of cracks in sintered nanosilver. Practical implications: During chip packaging processes, improving processes to reduce the porosity of sintered layers can delay the initiation of damage 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 plasticity constitutive model to analyze the mechanical behavior of sintered nanosilver with different porosities. It comprehensively investigates and explains the influence of porosity on the mechanical performance of sintered nanosilver across multiple scales.