A structure includes core substrates attached to a first side of a redistribution structure, wherein the redistribution structure includes first conductive features and first dielectric layers, wherein each core substrate includes conductive pillars, wherein the conductive pillars of the core substrates physically and electrically contact first conductive features; an encapsulant extending over the first side of the redistribution structure, wherein the encapsulant extends along sidewalls of each core substrate; and an integrated device package connected to a second side of the redistribution structure.