A method is for making an electronic device and includes forming an interconnect layer stack on a sacrificial substrate and having a plurality of patterned electrical conductor layers, and a dielectric layer between adjacent patterned electrical conductor layers. The method also includes laminating and electrically joining through an intermetallic bond a liquid crystal polymer (LCP) substrate to the interconnect layer stack on a side thereof opposite the sacrificial substrate. The method further includes removing the sacrificial substrate to expose a lowermost patterned electrical conductor layer, and electrically coupling at least one first device to the lowermost patterned electrical conductor layer.