Systems and methods for improving heat distribution and heat removal efficiency in PoP semiconductor packages are provided. A PoP semiconductor package includes a first semiconductor package that is physically, communicably, and conductively coupled to a stacked second semiconductor package. A gap forms between the upper surface of the first semiconductor package and the lower surface of the second semiconductor package. on an organic substrate. A curable fluid material, such as a molding compound, may be flowed both in the interstitial spaces between the PoP semiconductor packages and into the gap between the upper surface of the first semiconductor package and the lower surface of the second semiconductor package.