Vias in a metallic plane of a desired thickness with a dielectric by providing a layer of dielectric material (5) between two sheets (1, 2) containing clearance holes (3, 4) of the metal of the metallic plane wherein the total thickness of the two sheets corresponds to the desired thickness. Also provided on each sheet is a mask (6, 7) having clearance holes that correspond to the clearance holes in the sheets. On each mask is provided a layer of dielectric (8, 9) and on each layer of dielectric is provided a release layer (10, 11). The composite is laminated to thereby cause dielectric from the layer between the two sheets and the layers adjacent the mask to fill the clearance holes and to bond the metallic planes together. The mask, remaining dielectric adjacent the mask, and release layer are then removed.