Abstract: A thermal substrate includes a multilayer film, a first conductive layer adhered to the first outer layer of the multilayer film and a second conductive layer adhered to the second outer layer of the multilayer film. The multilayer film includes a first outer layer including a first thermoplastic polyimide, a core layer including a polyimide and a second outer layer including a second thermoplastic polyimide. The multilayer film has a total thickness in a range of from 5 to 150 ?m, and the first outer layer, the core layer and the second outer layer each include a thermally conductive filler. The first conductive layer and the second conductive layer each have a thickness in a range of from 250 to 3000 ?m.