Finite Element Analysis on Fracture Mechanics of Al 2 O 3 , AlN and Si 3 N 4 -based Substrates under Thermal Shock Condition

The CTE mismatch of copper metallization and Al 2 O 3 ceramics deteriorated package reliability of power electronics. Stresses in metal-ceramics interface initiate cracks and delamination when facing with thermal shock condition. Consequently, researches on bonding metals and ceramics to replace DBC have been given more emphasis. Among them, directed bonding aluminum (DBA) and AlN, Si 3 N 4 ceramics are potential substitutes. In our study, the groups of Al 2 O 3 , AlN and Si 3 N 4 -based substrates were investigated to compare the fracture properties under thermal shock condition. Fracture mechanical parameters such as stress intensity factors K I , K II and J-integral were calculated with regard to various groups. Besides, various geometric layouts of edge tail for metallization were compared to demonstrate their effects on enhancing fracture toughness. By this work, the fractural reliability of these substrates is helpful to guide the selection of substrates for power modules.