A device includes a first die, a second die, one or more redistribution layers (RDLs) electrically connected to the first die, a plurality of connectors on a surface of the one or more RDLs and a package substrate electrically connected to the first die and the second die. The package substrate is electrically connected to the first die through the one or more RDLs and the plurality of connectors. The package substrate comprises a cavity, and the second die is at least partially disposed in the cavity.