A new and effective drop test evolution to next-gen handheld applications

Drop test performance is one of the key reliability parameters for characterizing electronic packages such as ball grid array (BGA) under mechanical stresses. It is especially important for a large BGA in a handheld device such as a smart-phone or tablet where the solder joint tends to crack under mechanical stress. This has gained more and more interest as mobile computing becomes dominant for next generation handheld applications. The JEDEC test board is widely used in the industry to calibrate the drop performance of solder joints in BGA and other area array components. One main drawback for this test method is in its test vehicle, which is a 132mm×77mm rectangular board populated a 3×5 array of BGAs. The stress and strain at each component behaves differently dependent to the distance of each component to the center and or screw holes used for mounting on the table. This makes statistical and quantitative analysis of the drop test results impossible unless a large number of sample sizes is used. This paper demonstrated two types of square board with 4 components mounted symmetrically on the top. This significantly improves the efficiency of drop test by making all data points undergo the same stress level so that a consistent drop and a good statistical analysis is feasible.