Semiconductor package and method of fabricating the same

A semiconductor package, comprising:

• a lower package including a lower package substrate and at least a first semiconductor chip disposed thereon;
• an interposer stacked on the lower package, the interposer:
• including internal wires and a plurality of insulating layers,
• having an upper surface and a lower surface, and
• including an upper recess at the upper surface and a lower recess, opposite the upper recess, at the lower surface;
• an upper package including an upper package substrate and at least a second semiconductor chip disposed thereon;
• and
• a lower heat transfer layer formed of a thermal interface material, the lower heat transfer layer disposed in the lower recess and thermally connecting the first semiconductor chip to at least a first internal wire of the interposer.

A method of fabricating a semiconductor package, comprising:

• forming lower conductive connecting portions on a lower package substrate;
• mounting a lower semiconductor chip on the lower package substrate provided with the lower conductive connecting portions;
• forming a lower heat-transfer layer on the lower semiconductor chip;
• stacking an interposer, including an interposer substrate and upper conductive connecting portions attached to a bottom surface of the interposer substrate, on the lower semiconductor chip, in such a way that the upper conductive connecting portions are attached to the lower conductive connecting portions;
• performing a reflow process to the lower and upper conductive connecting portions to form conductive connecting portions;
• forming an under-fill resin layer between the lower package substrate and the interposer substrate;
• and
• stacking an upper package on the interposer.