Electrical linewidth test structures fabricated in mono-crystalline films for reference-material applications

Electrical linewidth measurements have been extracted from test structures replicated in thin planar films of mono-crystalline silicon with feature widths down to 0.18 μm. The structures are electrically insulated from a bulk-silicon substrate by a layer of silicon dioxide provided by SIMOX (Separation by the IMplantation of OXygen) technology. The motivation is to facilitate the development of linewidth reference materials for Critical-Dimension (CD) instrument calibration. Appropriate selection of the orientation of the starting silicon, relative to the orientation of the structures´ features, allows patterning by a lattice-plane selective etch thus providing the desired reference-feature properties of rectangular cross section and atomically planar sidewalls. These properties are highly desirable for CD-reference applications where feature widths must be certified with nanometer-level uncertainty for use by a diverse range of CD instruments. End applications include the development and calibration of new generations of CD instruments directed at controlling processes for manufacturing devices having sub-quarter-micrometer features