NOVELTY - An electronics structure comprises a substrate stack having a dielectric layer with metallic interconnect structure(s) within and a dielectric barrier layer above the dielectric layer; a multi-layer hardmask stack on the substrate stack and coated with a patterned self assembled layer; and a blocking layer on top of the self-assembled layer that blocks a portion of the pattern. The self-assembled layer pattern is nanoscale and/or microscale voids generated into the dielectric barrier layer and into the dielectric layer next to the metallic interconnect structure to create columns.    USE - Electronics structure for computers (claimed); servers; mainframes; datacom routers; telecom routers; electronic devices in, e.g. automobiles and airplanes; camera equipment; computer equipment, i.e. printers, fax machines, and scanners; household appliances; and personal electronic devices, i.e. compact disc players, digital versatile disc-players, and cassette tape recorders.    ADVANTAGE - The electronics structure is prepared using a sacrificial multilayer hardmask scheme.    DETAILED DESCRIPTION - An electronics structure comprises a substrate stack having a dielectric layer with metallic interconnect structure(s) within and a dielectric barrier layer above the dielectric layer; a multi-layer hardmask stack on the substrate stack and coated with a patterned self assembled layer; and a blocking layer on top of the self-assembled layer that blocks a portion of the pattern. The self-assembled layer pattern is nanoscale and/or microscale voids generated into the dielectric barrier layer and into the dielectric layer next to the metallic interconnect structure to create columns (less than 0.1, preferably 0.05-0.5 mu m in length) in the dielectric barrier layer and dielectric layer. The substrate comprises semiconductor chip, microfluidic array, and/or micro fuel cell. The self assembled layer is a diblock copolymer.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of the multilayer hardmask.    Dielectric deposition (4240)