A planarization process, such as chemical and mechanical polish (CMP), may optionally be performed to remove excess portions of the molding material 130 over the front side of the die 120. After the planarization process, the molding material 130, the conductive pillar 119, and the die connectors 128 have a coplanar upper surface, in some embodiments.

Referring next to FIG. 4, a redistribution structure 140 (may also be referred to as a front side redistribution structure) is formed over the molding material 130, the conductive pillar 119, and the die 120. The redistribution structure 140 comprises one or more layers of electrically conductive features (e.g., conductive lines 143, vias 145) formed in one or more dielectric layer (e.g., 142, 144, 146, and 148).

In some embodiments, the one or more dielectric layers (e.g., 142, 144, 146, and 148) are formed of a polymer, such as polybenzoxazole (PBO), polyimide, benzocyclobutene (BCB), or the like; a nitride such as silicon nitride; an oxide such as silicon oxide, phosphosilicate glass (PSG), borosilicate glass (BSG), boron-doped phosphosilicate glass (BPSG), or the like. The one or more dielectric layers may be formed by a suitable deposition process, such as spin coating, chemical vapor deposition (CVD), laminating, the like, or a combination thereof.