Multi-layer circuit device

PURPOSE: To provide high structural strength and to reduce a capacitive coupling between extended conductors by providing a plurality of electrically conductive connecting columns and wall members for supporting these connecting columns, etc., so that air exists between the wall members. CONSTITUTION: An integrated circuit having an air-dielectric, for which air is used as an insulator, i.e., as a dielectric, is formed. There are provided a first layer 10 on which patterned conductors 16, 18 are formed, and a plurality of electrically conductive columns 12 which are connected to predetermined connection points on the conductors 16, 18, respectively. Further, there are provided wall members 14 of an insulating material, formed between these columns 12, for supporting the connecting columns 12, and extended conductor 18 connected to the upper end of each of the connecting columns 12 selected from among the plurality of connecting columns. Then, air is caused to exist between the wall members 14. Thus, this structure can be used for a conductor extending over a running distance of longer than 100 microns.