Trace-Based Thermo-Mechanical Warpage Analysis of Multilayer PCB Substrates and Sensitivity Study on Support Conditions

This study presents a trace-informed thermo-mechanical analysis framework for predicting Warpage behavior in multilayer Printed Circuit Boards (PCBs) during the reflow process. A seven-layer PCB composed of FR-4, Copper, and Prepreg is modeled. Electronic computer- aided design (ECAD)-derived layer Copper (Layer-Cu) and zone Copper (Zone-Cu) data are incorporated into effective material properties to represent spatial heterogeneity in stiffness and thermal expansion. A transient thermal analysis based on an IPC-compliant reflow temperature profile is sequentially coupled with structural analysis in ANSYS to evaluate temperature evolution, Out-of-plane deformation, and stress distribution. Five representative mechanical support configurations, including Weak springs, Simple support, 3-point support, Carrier support, and Rail support, are examined under different convection conditions. The results show that mechanical support conditions strongly influence both the magnitude and deformation mode of PCB Warpage under identical thermal loading. Carrier support and Rail support configurations more realistically represent reflow process constraints, whereas 3-point support results in localized deformation and relatively conservative Warpage responses. Variations in convection coefficients affect the absolute Warpage magnitude but do not alter the relative Warpage trends among different support conditions. Overall, the proposed framework clarifies the combined effects of Copper distribution asymmetry, transient thermal gradients, and mechanical constraints on PCB Warpage behavior.