Applying Anand model to low-temperature sintered nanoscale silver paste chip attachment

Tensile behaviors of low-temperature sintered films of a nanoscale silver paste used for chip-attachment are studied. Stress-strain curves of partially sintered films were measured at different temperatures and strain rates on a dynamic mechanical analyzer (DMA). The tensile strength of the sintered silver films decreased with increasing temperature or with decreasing strain rate. Then the uniaxial tensile inelastic deformation behaviors of the material were simulated by a unified visco-plastic constitutive model, Anand model. Finally, finite element simulation of chip-attachment using this interface material under thermal cycling was done with Anand model via ANSYS software. The simulation results showed that accumulation of plastic strain took place in the silver-bonding layer during thermal cycling, which might lead to the final failure of the chip-attachment.