Analytical Study on the Warpage Deformation of Die Attach Structure in Power Devices

According to the theory of elastic-plastic mechanics, the stress and deformation of a die attach structure under a temperature load were studied. An analytical relation between the deformation and the material physical parameters (coefficient of thermal expansion, Young’s modulus, yield stress, tangent modulus, and Poisson’s ratio) and geometric dimensions (thickness and length) was established, and the correctness of the relation was verified through experiments. The trends of the experimental and calculated values were consistent, with errors of about 20%. The increase in interconnect layer thickness and chip thickness and the decrease in chip length are beneficial to reduce the warping deformation.