Investigation on Hygro-Thermo-Mechanical Stress of a Plastic Electronic Package. (12th August 2014)

• Record Type: Journal Article
• Authors: Su, F.; Li, W.-J.; Lan, T.-B.; Shang, W.
• Is Part Of: Journal of mechanics. Volume 30:Number 6(2014)
• Page Start: 625
• Page End: 630
• Publication Date: 2014-08-12
• Subjects: Plastic electronic package -- Moistue diffusion -- Finite element method -- Hygro-thermo-mechanical stress -- Moiré interferometry; Mechanics, Analytic -- Periodicals; Mechanics -- Periodicals; 620.1005
• DOI: 10.1017/jmech.2014.52
• Languages: English
• ISSNs: 1727-7191

Abstract

Abstract : Plastic packaging materials tend to absorb moisture from ambient environment and get swollen, this may raise hygro-stress in plastic electronic package and redistribute the internal stress. In this paper, we reviewed the dramatic deformation of a plastic package (Flip Chip Plastic Ball Grid Array-FCPBGA) due to moisture absorption first, then hygro-thermo-mechanical stress of the plastic package and its evolution during a period of three months were investigated with finite element method, user development was performed for this investigation. The finite element model was verified with hygro-thermal deformation of the FCPBGA measured with a 3-D moiré interferometry system. Following findings were obtained: A. Thermal stress field was changed a lot due to moisture absorption; B. Thermal stress of chip was released to some extent, but peal stress up to 62.2MPa occurred to the solder bump, thus the danger of Under Bump Metal (UBM) opening increased.