Unstable Void Growth in Thermohyperelastic Plastic IC Packaging Material due to Thermal Load and Vapor Pressure

In this paper, a representative material cell containing a single microvoid is used to investigate void growth under combined vapor pressure and thermal stress. The plastic IC packaging material is assumed to be Gent-Thomas thermohyperelastic materials. Using the theory of cavity formation and unstable void growth in incompressible hyper-elastic material, we gained an analytical relation between the applied traction and the change of temperature. Numerical analysis is given of such polymers electronic packaging materials occurred "Popcorn" critical load burst. Numerical results indicate that the critical stress for unstable void growth is very sensitive to the change of temperature. The critical stress for unstable void growth at reflow temperature is likely to be much lower than that at room temperature.