A method includes attaching a voltage regulator to a first redistribution structure of a first package. A second redistribution structure is formed over the voltage regulator, the voltage regulator being embedded in the second redistribution structure. The first substrate is attached to the second redistribution structure to form a second package including the first package. A first voltage may be provided to the second redistribution structure and through the second redistribution structure to the voltage regulator. The voltage regulator regulates the first voltage into a second voltage and provides the second voltage through the first redistribution structure to a first device die, where an output of the voltage regulator is attached directly to the first redistribution structure.