Finite Element Simulation of Hillock Formation in Aluminum Interconnect

A non-linear finite element model has been used to simulate hillock formation in an aluminum interconnect structure. The hillock formation is caused by the thermal expansion mismatch between aluminum and the surrounding SiO2 passivation. Using the ABAQUS software [1], a large strain elastic-plastic-creep analysis was done. The results showed there were stresses large enough to cause yield and permanent deformation of the aluminum interconnect.