Introduction

Reference sample for the calibration of length measurements at the nanoscale, composed of a silicon substrate comprising several areas with calibration patterns for AFM tips or for grain measurement using grazing angle X-ray techniques (GISAXS, GIXRF).

The patterns are rows of holes with a calibration pitch varying between 35 and 15 nanometers, obtained using directional block copolymer technology.

Technical features

This standard of length is innovative since in commerce there are no similar products under 100 nanometers. By varying the molecular weight of the block copolymers used, it is possible to obtain different periodicities, with a very high regularity provided by the natural length constant originating from the molecular weight of the copolymer. By means of a gaseous chemical attack (RIE, Reactive Ion Etching), the array of cylinders in which the copolymer is segregated, is propagated to the underlying silicon. The silicon chip has various areas, some more extensive, where the arrays of nanometric holes are arranged in grains with different orientations, for the calibration of X-ray techniques at grazing angle, and some more restricted areas, similar to horizontal or vertical trenches, where the self-assembly of the copolymers produces mono-domain structures, with perfectly aligned and equidistant lines. This research activity is at TRL 4.

Possible Applications

• Calibration system for all Atomic Force microscopies, nano spectroscopy systems, such as TERS, nanoFTIR, thermal AFM, nanoRaman, practically all microscopy and nanoscale spectroscopy instrumentations.

Advantages

• Currently, there are no nanoscale length standards of these lattice steps on the market, the manufacturing method is precise and economical, and it is very flexible for the production of calibration patterns of different types and sizes.