• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2026, Vol. 62 ›› Issue (10): 137-145.doi: 10.3901/JME.260497

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Simulation Study on Moisture Diffusion Behavior of PBGA Devices under Hygrothermal Coupling Conditions

ZHANG Yunxuan1, WANG Shang1,2, SA Zicheng1, WEN Jiayue2, XU Shimeng3, LIN Pengrong3, CHEN Linfeng3, TIAN Yanhong1,2   

  1. 1. State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin 150001;
    2. Harbin Institute of Technology Zhengzhou Research Institute, Zhengzhou 450000;
    3. Beijing Microelectronics Technology Institute, Beijing 100076
  • Received:2025-05-17 Revised:2025-12-07 Published:2026-07-29

Abstract: Non-hermetic structures like plastic encapsulation in electronic devices are sensitive to environmental moisture. Moisture-induced property changes and stresses critically impact reliability. This study combined hygrothermal aging tests with molecular dynamics simulations to investigate dynamic moisture diffusion within plastic ball grid array(PBGA) packaging. Moisture diffusion parameters under varying conditions were fitted to calibrate the concentration-dependent diffusion coefficient. Implementing this dynamic model in hygro-thermal coupling simulations significantly improved prediction accuracy. Results reveal both Fickian and non-Fickian diffusion modes, with the diffusion coefficient decreasing nearly linearly as average moisture concentration increases. The optimized coupling equations outperform conventional constant-coefficient models in predicting internal moisture distribution. The proposed fitting model and simulation methodology offer a novel approach for predicting the behavior of plastic-encapsulated devices in humid environments, holding practical implications for reliability assessments concerning the storage, interconnection, and long-term operation of electronic devices.

Key words: moisture diffusion, hygrothermal coupling, composites, molecular dynamics, electronic packaging

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