Predicted stresses in ball-grid-array (BGA) and column-grid-array (CGA) interconnections in a mirror-like package design

• Published in: Journal of materials science. Materials in electronics 2016-03, Vol.27 (3), p.2430-2441
• Main Authors: Suhir, E., Ghaffarian, R., Nicolics, J.
• Format: Article
• Language: English
• Subjects: Assemblies; Characterization and Evaluation of Materials; Chemistry and Materials Science; Columns (structural); Design analysis; Design engineering; Devices; Materials Science; Optical and Electronic Materials; Solders; Stresses
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-015-4042-8

There is an obvious incentive for using bow-free (temperature change insensitive) assemblies in various areas of engineering, including electron device and electronic packaging fields. The induced stresses in a bow-free assembly could be, however, rather high, considerably higher than in an assembly, whose bow is not restricted. The simplest and trivial case of a bow-free assembly is a tri-component body, in which the inner component is sandwiched between two identical outer components (“mirror” structure), is addressed in our analysis, and a simple and physically meaningful analytical stress model is suggested. It is concluded that if acceptable stresses (below yield stress of the solder material) are achievable, a mirror (bow-free, temperature-change-insensitive) design should be preferred, because it results in an operationally stable performance of the system.