| 摘要 |
Specifications of a flip chip package and mold compound for a package are provided to a mold flow simulator and locations of void formation in the package during molding, identified. Subsequently, a substrate ( 124 ) for the package is designed with vias ( 206 ) at the locations of void formation. During molding, air pockets at the locations of void formation escape through the vias ( 206 ) and vents ( 116 ) in the lower cavity bar ( 110 ), as mold compound flows between the die and the substrate ( 124 ) and forces the air out. In addition, the lower cavity bar ( 110 ) has a down set central location ( 114 ), which allows air to pass from the vias ( 206 ) to the vents ( 116 ). In addition, as the diameter of a via ( 206 ) is between 20-30 microns, more area on the lower surface of the substrate ( 124 ) is available for terminals arranged in an array.
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