Which Parameter Matters Most? A Structured Literature Review and Unified Simulation Comparison of Design and Material Influences on PCBA Solder-Joint Lifetime

Abstract

This paper presents a condition-controlled, simulation-based ranking of five key design and material parameters governing solder-joint fatigue life in printed circuit board assemblies (PCBAs) under thermal cycling: substrate material, substrate thickness, copper thickness, solder alloy, and solder thickness. All parameters are evaluated under identical boundary conditions following the JEDEC JESD22-A104 reference profile using a parametric pySherlock-driven finite-element workflow anchored against independent hardware results from the SesiM research project. Within the studied envelope, substrate material is identified as the numerically dominant lifetime parameter, shifting predicted time-to-failure by close to an order of magnitude more than any geometric parameter within practical design ranges, with intrinsic differences in coefficient of thermal expansion (CTE), stiffness, and viscoelastic response identified as the primary drivers rather than glass-transition proximity alone. This dominance is most pronounced when the operating temperature approaches the glass-transition temperature of the laminate; for the majority of applications operating well within the limits of standard FR-4, solder-joint thickness emerges as the most influential design-stage lever, scaling lifetime nearly linearly across the studied range. A mission-profile-resolved analysis further demonstrates that solder-alloy ranking depends on the absolute temperature window even at constant temperature swing, highlighting the limitations of single-profile alloy benchmarking. Furthermore, the proposed workflow makes condition-controlled, multi-parameter studies of this scope feasible in simulation rather than in hardware, providing a practical screening methodology that reduces the characterization effort from years to days and supports reliability-oriented PCBA design at an early stage.