2024

Vol.31 No.2

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  • Journal of the Microelectronics and Packaging Society
  • Volume 30(4); 2023
  • Article

Review

Journal of the Microelectronics and Packaging Society 2023;30(4):50-60. Published online: Feb, 20, 2024

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DOI : doi.org/10.6117/kmeps.2023.30.4.050

A Numerical Study on the Effect of Initial Shape on Inelastic Deformation of Solder Balls under Various Mechanical Loading Conditions

  • Da-Hun Lee1 , Jae-Hyuk Lim1 , and Eun-Ho Lee1,2,3†
    1School of Mechanical Engineering, Sungkyunkwan University, Seobu-ro 2066, Suwon-si, Gyeonggi-do, 16419, Republic of Korea, 2Department of Smart Fab. Technology, Sungkyunkwan University, Seobu-ro 2066, Suwon-si, Gyeonggi-do, 16419, Republic of Korea, 3Department of Intelligent Robotics, Sungkyunkwan University, Seobu-ro 2066, Suwon-si, Gyeonggi-do, 16419, Republic of Korea
Corresponding author E-mail: e.h.lee@skku.edu
Abstract

Ball Grid Array (BGA) is a widely used package type due to its high pin density and good heat dissipation. In BGA, solder balls play an important role in electrically connecting the package to the PCB. Therefore, understanding the inelastic deformation of solder balls under various mechanical loads is essential for the robust design of semiconductor packages. In this study, the geometrical effect on the inelastic deformation and fracture of solder balls were analyzed by finite element analysis. The results showed that fracture occurred in both tilted and hourglass shapes under shear loading, and no fracture occurred in all cases under compressive loading. However, when bending was applied, only the tilted shape failed. When shear and bending loads were combined with compression, the stress triaxiality was maintained at a value less than zero and failure was suppressed. Furthermore, a comparison using the Lagrangian-Green strain tensor of the critical element showed that even under the same loading conditions, there was a significant difference in deformation depending on the shape of the solder ball.

Keywords Numerical analysis, Inelastic deformation, Fracture, Solder, Packaging

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