In an embodiment, a device includes: a processor die including circuit blocks, the circuit blocks including active devices of a first technology node; a power gating die including power semiconductor devices of a second technology node, the second technology node larger than the first technology node; and a first redistribution structure including first metallization patterns, the first metallization patterns including power supply source lines and power supply ground lines, where a first subset of the circuit blocks is electrically coupled to the power supply source lines and the power supply ground lines through the power semiconductor devices, and a second subset of the circuit blocks is permanently electrically coupled to the power supply source lines and the power supply ground lines.