Abstract: A multilayer semiconductor device includes at least one structure for transmitting electrical signals, and in particular, microwave signals. The device includes at least one electrically conductive enclosure that includes a bottom plate and a top plate in two different layers. Lateral walls connect the bottom and top plates. Electrically conductive connecting strips extend into the enclosure and are in an intermediate layer, and are electrically insulated from the enclosure. The enclosure has at least one passage through which extends electrical connections of the connecting strips, which are also electrically insulated from the enclosure.