Evaluation of reliability of lotus-type porous Cu joint soldered by SAC305

초록

Lotus-type porous Cu (LPC) is a metallic material characterized by its cylindrical pore structure, which exhibits excellent thermal conductivity, fluid permeability, ductility, and impact energy absorption capabilities. To evaluate the applicability of LPC as electronic materials, LPC/dissimilar materials joints were fabricated using SAC305 solder. To consider the pore structure in LPC, the solder filling ratio was focused as key variables in this work. The microstructure, mechanical behaviors and thermal shock behavior of LPC joints were examined. As the solder filling ratio increased, the joint strength increased, while ductile behavior decreased. When the pores were filled by solder (solder filling ratio: 100 %), the shear strength was similar to that of the non-porous Cu joint. After thermal shock cycling, LPC joint demonstrated lower degradation of shear strength compared to the nonporous Cu joint due to its structural characteristics. These results were attributed to the low yield strength of LPC and unique joining interface by pore structure of LPC.

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