Through-silicon-via (TSV) and redistribution-layer (RDL) interconnects are essential for high-density three-dimensional (3D)/2.5D integration in aerospace microsystems. However, their reliability under energetic electron irradiation remains insufficiently understood, particularly regarding coupled electro-thermal-mechanical degradation mechanisms. This study aims to elucidate the multiphysics response of TSV-RDL structures under electron irradiation and identify key structural parameters governing radiation-induced failure, providing guidance for radiation-hardened packaging design.
A coupled Geant4-COMSOL framework was established to simulate 1 MeV electron irradiation on TSV-RDL architectures. Monte-Carlo particle transport was used to extract spatial energy deposition and charge generation profiles, which were subsequently imported into a multiphysics finite element solver to analyze electrostatic field distortion, irradiation-induced thermal loading and interfacial stress evolution. Structural parameter sweeps were conducted to evaluate the effects of dielectric thickness around TSVs and at the top–bottom oxide layers. Experimental scanning electron microscope (SEM) observations were used to validate stress localization and damage morphology.
Multiple scattering dominates electron energy dissipation (approximately 77.6%), leading to concentrated charge accumulation at TSV-silicon dioxide (SiO2) interfaces and electric field intensification up to 4.55 × 10–2 MV/cm. Energy deposition triggers localized thermal expansion mismatch, resulting in peak von Mises stress of approximately 115.5 MPa at TSV-to-RDL transition regions. Increasing irradiation dose from 0 to 350 Mrad significantly accelerates stress buildup and interfacial risk. An optimal dielectric configuration was identified; SiO2 thickness of approximately 24–26 µm (top/bottom layers) and approximately 14–16 µm (TSV liners) minimizes electric field concentration and improves mechanical robustness. SEM inspection confirmed cracking at predicted stress concentration regions, validating the modeling framework.
This work provides a comprehensive electro–thermal–mechanical analysis of TSV-RDL structures under high-energy electron exposure using a physics-coupled Geant4-COMSOL approach. The findings clarify radiation-driven multiphysics failure mechanisms and propose dielectric thickness optimization as an effective radiation-hardened packaging strategy. Results serve as a theoretical basis for designing reliable TSV-RDL interconnects in aerospace microelectronics and extreme-environment microsystems.
