Semiconductor packages with integrated heat spreaders

Abstract

One implementation of present disclosure includes a semiconductor package stack. The semiconductor package stack includes an upper package coupled to a lower package by a plurality of solder balls. The semiconductor package stack also includes a lower active die situated in a lower package substrate in the lower package. The lower active die is thermally coupled to a heat spreader in the upper package by a thermal interface material. An upper active die is situated in an upper package substrate in the upper package, the upper package substrate being situated over the heat spreader. The thermal interface material can include an array of aligned carbon nanotubes within a filler material. The heat spreader can include at least one layer of metal or metal alloy. Furthermore, the heat spreader can be connected to ground or a DC voltage source. The plurality of solder balls can be situated under the heat spreader.