Two models are presented for analyzing BGA solder interconnects:(a) a model for predicting solder joint geometries after an upright orinverted reflow process, and (b) a reliability model for estimatingmaximum shear strain and fatigue life under a global thermal mismatchload condition. The reliability model includes a newly derivedclosed-form expression relating the maximum shear strain in a solderjoint to the load, material, and joint shape parameters. The models areused to generate design/processing guidelines that may be used toimprove the yield of a BGA soldering operation and the in-servicereliability of the interconnect. Potential benefits of using anon-uniform array (i.e., one including joints of different size andshape) are explored
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