Reliability studies and design improvement of mirror image CSP assembly

BGA Interconnection Reliability in Mirrored Module Configurations

“…[4]- [6] Mirrored structures, where similar components are located on opposite sides of a PCB, have been studied for chip scale package (CSP)/BGA modules, and some finite element modeling (FEM) data along with test results can be found in the literature [7]- [12]. Mirroring causes challenges in the areas of design and material, such as  Increased stiffness due to restricted warpage of the PCB [7], [8], which can be considered the single major issue affecting the lifetime of interconnections in mirrored module configurations  Microstructural effects due to a second reflow process, i.e., extended growth of rigid and brittle intermetallic phases  Differing interconnection heights of mirrored components, depending on the number of reflows they have been through (top/bottom side) [9]  Irregular solder joint shape, voids, partial separation between the solder and the intermetallic layer [10] Some proposed solutions to mitigate the increased stress levels have been considered, those being  Offsetting the mirrored components [7], [8]  Using a thinner PCB [11]  Using more compliant materials and smaller components [8]  Redesigning the solder pad [12] BGA Interconnection Reliability in Mirrored Module Configurations Juha Hagberg, Jussi Putaala*, Juha Raumanni, Olli Salmela, Timo Galkin T This article presents the results of thermal cycling tests (TCT) and simulations of plastic BGA (PBGA) components mounted on one side (single side configuration) and different mirrored configurations on a PCB. Anand's constitutive model [13] was used in the finite element analysis software to calculate dissipated creep energy densities in the interconnections.…”

Application of Multi-Computer Communication among Single-Chip Microcomputers on Distributed Data Acquisition

“…With the development of microcomputer, Single-chip microcomputers(SCM) has become one of the indispensable components in the DCS. Generally, a master SCM and several slave SCMs are composed in a DCS [2][3]. The main purpose of slave computers is to acquire signal data and send them to the master.…”

Comparison of results from empirical ALT test to CAE simulation for wireless clients

“…Chen et al (2006) investigated Sn3.5Ag0.75Cu solder joint reliability under thermal cycling. Xie and Yi (2002) employed the finite element modeling (FEM) to compare the stress and strain of a mirror image CSP and a single‐sided CSP. Previous research has performed empirical testing and simulations to characterize performance of soldering materials and innovated packaging technologies (Chen et al , 2006; Amagai, 1999; Zhang et al , 2006; Rajendra and Pendse, 2002; Kim et al , 2002; Zhao et al , 2006; Huang et al , 2009).…”