Provided are interconnect circuits for combined electrical and thermal energy transfer to devices connected to these circuits. Also provided are methods of fabricating such interconnect circuits. An interconnect circuit may include an electro-thermal conductor and at least one insulator providing support to different portions of the conductor with respect to each other. The insulator may include one or more openings for electrical connections and/or heat exchange with the electro-thermal conductor. The portions of the conductor may be electrically isolated from each other in the final circuit. Initially, these portions may be formed from the same conductive sheet, such as a metal foil having a thickness of at least about 50 micrometers. This thickness ensures sufficient thermal transfer in addition to providing excellent electrical conductance. In some embodiments, the conductor may include a surface coating to protect its base material from oxidation, enhancing electrical connections, and/or other purposes.