US Patent 11171208 High performance circuit applications using stacked 3D metal lines

Transistor/semiconductor devices and methods of forming transistor/semiconductor devices. The devices include a metal layer with dielectric isolation within existing 3D silicon stacks. Two different disposable materials within the 3D silicon stack are selectively removed later from other layers in the stack to become future metal layers and oxide layer respectively, to provide the metal line isolated in a vertical central portion of the stack.