Thermo-Mechanical Deformation and Stress Analysis of Flip-Chip Ball Grid Array

by Guo, Yu-Lun

Abstract (Summary)
The thesis investigates the thermo-mechanical deformation and stress of a flip-chip package (FCBGA) via both experiment and simulation. First, Shadow Moiré is used to evaluate the warpage of a package at elevated temperature. Then we adopt the finite element method incorporated with the software ANSYS to simulate the warpage of a package and compare the obtained results with experiment at data. Then, the material properties of underfill, the thickness of die and the substrate are considered as important parameters. Their effects on stress and strain fields of package are studied. In case of FCBGA with and without underfill, we find that FCBGA with underfill can reduce stress concentration and increase warpage of a package in comparion with FCBGA without underfill. As for FCBGA with and without heat slug, it is observed that the warpage of FCBGA with heat slug is smaller than that of FCBGA without heat slug. Both stress and strain in the packages of above two cases are similar. The parametric study about the underfill, we find that smaller modulus and CTEs of underfill can reduce the stress and strain of package. However in the consideration of thicknesses of both die and substrate, it is shown that thinner die can reduce stress and strain of package, but thinner substrate does not. So it is suggested that thicknesses of die are the thinner the better.
Bibliographical Information:

Advisor:Huang-Kuang Kung; Chorng-Fuh Liu; Jenq-Dah Wu; Ming-Hwa R. Jen

School:National Sun Yat-Sen University

School Location:China - Taiwan

Source Type:Master's Thesis

Keywords:ansys flip chip warpage


Date of Publication:07/01/2003

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