Patent ID: 7808053

Claim:
An apparatus comprising: a substrate including a central region and a peripheral region; a plurality of layers above a surface of the substrate, the plurality of layers covering at least a portion of the central region and at least a portion of the peripheral region adjacent to the portion of the central region covered by the plurality of layers, the plurality of layers including a mask layer overlaying the substrate and a hard mask layer overlaying the mask layer, the hard mask layer having a hard mask layer top surface; a first plurality of pitch-multiplied oxide spacers on the hard mask layer top surface, the first plurality of pitch-multiplied oxide spacers being above the central region of the substrate and including at least one pitch-multiplied oxide spacer having a substantially flat surface at a boundary between the central region and the peripheral region and a curved surface extending from the hard mask layer top surface up to the substantially flat surface; and a second plurality of pitch-multiplied oxide spacers on the hard mask layer top surface, the second plurality of pitch-multiplied oxide spacers above the peripheral region and including at least one pitch-multiplied oxide spacer having a substantially flat surface at a distance from the at least one pitch multiplied oxide spacer having the substantially flat surface at the boundary, the distance no less than a width at the hard mask layer top surface between two of the plurality of pitch-multiplied oxide spacers above the central region, and no more than a width at the hard mask layer top surface of a second mask above an interconnect in the peripheral region and adjacent to the boundary.