MEMS Diffractive Optical Nanoruler Technology for Tipbased Nanofabrication and Metrology

This paper reports on a diffractive optical nanoruler used to guide tip-based nanofabrication. A precision of plusmn3 times 10^-4 has been demonstrated across a 75 mm wafer; we can account for errors external to the system which reduce this figure to plusmn1.5 times 10^-5. A microfabricated aluminum grating diffracts an external cavity laser beam stabilized to the rubidium D2 line (780 nm). The resulting hexagonal lattice intensity pattern guides a PC-board assembly, consisting of a quadrature photodiode and an STM tip, on a flexural piezo stage. The STM tip is used to make indentations in resist spun on an Al film deposited on a silicon wafer. The precision is measured using electron microscopy by locating the indentations.