A Study of Factors Affecting Process-Induced Warpage Behavior of Flip Chip Package on Package

This study attempts to investigate the crucial factors affecting the warpage behavior of flip chip package on package (fcPoP) during fabrication. To characterize the process-induced warpage, a process-dependent simulation methodology that integrates ANSYS element death/birth technique and finite element analysis (FEA) is introduced. For modeling simplicity, the core and coreless substrates are transformed into an equivalent homogenized material, and their effective thermal-mechanical properties are determined using a proposed effective model based on FEA and trace mapping feature in ANSYS. The predicted effective mechanical properties are compared with those obtained by the rule-of-mixture analytical model and also the detailed FEA as a benchmark. Besides, the predicted process- induced warpages during the fabrication process are validated against experimental data.