Electrically isolated power device package

A packaged power device includes a substrate (28) including a first conductive layer (30), a second dielectric layer (32), and a third conductive layer (34). The first conductive layer is bonded to the second dielectric layer, and the second dielectric layer is bonded to the third conductive layer. The first and third conductive layers are electrically isolated from each other. The substrate has a lower surface. A semiconductor die (26) is bonded to the first conductive layer of the substrate. A plastic package (36) encloses the die and has a lower surface. A curved backside includes the lower surfaces of the plastic package and substrate.