はんだりフロー時のLSI封止樹脂割れに対する強度評価

概要

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A crack initiated from a v-notch corner in the molding resin such as a corner of die pad is one of the main causes of the failure of plastic packages. The stress intensity factors of the asymptotic soiution of a corner of jointed dissimilar materials are utilized for the evaluation of a solder reflow crack in a quad flat package (QFP). At first, we estimate the critical vapor pressure, which causes a crack from a corner in the molding resin, using the critical stress intensity factor of a v-notch corner measured by v-notched three points bending tests and the displacement extrapolation method with the three dimensional (3-D) finite element method (FEM). Moisture concentration in the QFP after absorbing moisture is analyzed, and vapor pressure caused by the solder reflow process is estimated. The critical moisture absorption time, which results in crack occurrence during the solder reflow process, can be predicted by this evaluation technique. Furthermore, we perform infrared solder reflow tests of the QFP for verifying the present failure evaluation technique.
一般社団法人日本機械学会の論文
1999-08-25