The warpage issue of three-dimensional multi-chip module (3D-MCM) was discussed by using finite element (FE) simulation with viscoplastic solder model and large deformation theory.The comparison results show that the existence of the cavity in the embedded substrate results in the double-bow warpage mode of substrate

the viscoplasticity of solder balls results in the residual warpage of 3D-MCM during the temperature cycling.The cavity in the center of substrate can decrease the warpage of 3D-MCM.The application of underfill could strengthen the interconnection between device and substrate

and decrease the residual warpage of 3D-MCM after temperature cycling.However

the large CTE (coefficient of thermal expansion) of underfill might incur other new failure models.Finally experimental results by Moiré fringes pattern validated the predication of warpage by the simulation with viscoplastic solder model.