A device includes a device layer comprising a first transistor; a first interconnect structure on a front-side of the device layer; and a second interconnect structure on a backside of the device layer. The second interconnect structure includes a first dielectric layer on the backside of the device layer; a contact extending through the first dielectric layer to a source/drain region of the first transistor; a conductive line electrically connected to the source/drain region of the first transistor through the contact; and a thermal dissipation path thermally connected to the device layer, the thermal dissipation path extending to a surface of the second interconnect structure opposite the device layer. The thermal dissipation path comprises a dummy via.