Distribution of a minor solid constituent in a transfer molded e-pad leadframe package

This study investigates the spatial distribution of a minor particulate constituent in a transfer molded exposed die paddle (e-pad) leadframe microcircuit package. Packages were polished at three depths parallel to its top surface. Levels 1 and 2 are above the die and leadframe while level 3 is just below the top surface of the die and leadframe. The distribution of area fraction and size of the particulate was analyzed for each level and with respect to the distance from the gate using micro-photographic image analysis. A nonuniform distribution of the particulate material for both particle size and location is evident, and its relations with gate, die, and leadframe are interpreted. ANOVA tests were conducted to assess the statistical significance of the variations.