The effects of wire geometry and wire layout on wire sweep performance using LQFP packages in transfer mold

作者：Ali Siti Sofiyah Skh; Hian Serene Teh Seoh; Ang Bee Chin^*

来源：International Journal of Precision Engineering and Manufacturing, 2014, 15(9): 1793-1799.

DOI：10.1007/s12541-014-0531-6

• LQFP
• Wire geometry
• Wire layout
• Wire sweep measurement

Transfer molding is the most effective method for molding encapsulation for semiconductor packaging due to low maintenance cost and high production yield. Wire sweep is a critical moldability issue as excessive wire sweep will contact neighbouring wires, causing electrical short that consequently leads to electrical failure of the package. Wire sweep characterization was carried out with various wire locations, mold flow directions, wire lengths, wire pitches and wire angles on Low Quad Flat Packages (LQFP). JMP statistical analysis was performed to determine the significant factors and correlations of wire sweep performance. It was found that wire length has the most significant correlation with wire sweep percentage. The four wires, two at the bottom-left and top-right (and hence designated as corner 2 and 4, respectively) exhibited the worst wire sweep when the mold gate was located at the top-left corner of the package. The wire sweep performance of seven wire layouts with varying wire lengths were also investigated. The results have revealed and proven that the two wires (corner 2 and 4, respectively) exhibited a higher wire sweep percentage. Overall, it was found that wire X4 has the highest wire sweep deflection.

• 出版日期2014-9