ISSN:
1741-2765
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract A comprehensive evaluation of the thermally induced warping in two microcircuit modules of differing substructure has been made using holographic interferometry. The measured out-of-plane displacement pattern for the ‘symmetric/large-hole’ module was found to be very simple, stable, and repeatable, while for the ‘asymmetric/small-hole’ module it appeared to be highly complex, of changing shape and stable only after several test cycles. Quantitative analysis of these results demonstrate that changes in the internal structure of the multilayer printed wiring board can have a significant impact on the loadings experienced by solder-post connections between the chip carrier and the printed wiring board during normal power cycles. These include changes in the bending pattern sufficient to almost halve the peak Mode B (bending) deformations of the solder posts. At the same time, the associated decreases in local deformation and deformation gradients result in a 33-percent decrease in the peak Mode C (tensile) deformation of these same critical connections.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02329132
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