A semiconductor package structure, comprising: a first carrier substrate having a first surface and an opposing second surface; a second carrier substrate stacked on the first carrier substrate and having a first surface and an opposing second surface that faces the first surface of the first carrier substrate; a semiconductor die mounted on the first surface of the second carrier substrate; and a heat spreader disposed on the first surface of the first carrier substrate to cover and surround the second carrier substrate and the semiconductor die; and a first encapsulating material having a first portion covered by the heat spreader, wherein the second carrier substrate and the semiconductor die are surrounded by the first portion of the first encapsulating material, wherein the first encapsulating material further comprises a second portion surrounding an exterior sidewall of the heat spreader; or a first encapsulating material having a first portion covered by the heat spreader, wherein the first encapsulating material further comprises a second portion surrounding an exterior sidewall of the heat spreader; and a second encapsulating material disposed on the first surface of the second carrier substrate and surrounding the semiconductor die; wherein the heat spreader covers and surrounds the second encapsulating material, and wherein the second carrier substrate and the second encapsulating material are surrounded by the first portion of the first encapsulating material; characterised in that the semiconductor package structure further comprises at least one capacitor mounted on the second surface of the second carrier substrate, wherein the at least one capacitor is surrounded and supported by the first encapsulating material or by an underfill material layer interposed between the first carrier substrate and the second carrier substrate. a first carrier substrate having a first surface and an opposing second surface; a second carrier substrate stacked on the first carrier substrate and having a first surface and an opposing second surface that faces the first surface of the first carrier substrate; a semiconductor die mounted on the first surface of the second carrier substrate; and a heat spreader disposed on the first surface of the first carrier substrate to cover and surround the second carrier substrate and the semiconductor die; and a first encapsulating material having a first portion covered by the heat spreader, wherein the second carrier substrate and the semiconductor die are surrounded by the first portion of the first encapsulating material, wherein the first encapsulating material further comprises a second portion surrounding an exterior sidewall of the heat spreader; or a first encapsulating material having a first portion covered by the heat spreader, wherein the first encapsulating material further comprises a second portion surrounding an exterior sidewall of the heat spreader; and a second encapsulating material disposed on the first surface of the second carrier substrate and surrounding the semiconductor die; wherein the heat spreader covers and surrounds the second encapsulating material, and wherein the second carrier substrate and the second encapsulating material are surrounded by the first portion of the first encapsulating material; characterised in that the semiconductor package structure further comprises at least one capacitor mounted on the second surface of the second carrier substrate, wherein the at least one capacitor is surrounded and supported by the first encapsulating material or by an underfill material layer interposed between the first carrier substrate and the second carrier substrate.