Scalable Throughput and Stable Scanning Probe Nanolithography Based on Local Anodic Oxidation by Arrayed Wear-Insensitive Sidewall Microprobes

Abstract

In this paper, scalable throughput and stable scanning probe nanolithography is demonstrated using arrayed wear-insensitive sidewall probes (WISPs). Tips of the proposed arrayed probes have a uniform cuboid shape. Each probe tip consists of a microscale mechanical contact and two separated nanoscale electrical contacts (sidewall electrodes) formed on the sidewall of the mechanical contact, and an eave formed at the end. The microscale mechanical contacts reduce the tip wear by dispersing the force applied to the tip, and the nanoscale electrical contacts enable the drawing of nanoscale features. The eaves at the end of the cantilevers play an essential role in preventing metal from being deposited on the mechanical contact, which simplifies the fabrication process. Even when the probe is mechanically worn, the width of the sidewall electrodes does not change; this ensures the wear-insensitive performance of the probe over long drawing distance. A microelectromechanical systems technique is used to fabricate the arrayed probes. Eight linearly arrayed WISPs with an 80- $\mu \text{m}$ -wide mechanical contact and two 30-nm-thick electrical contacts are fabricated. Using the fabricated probes, eight sets of patterns with a line width of $\sim 100$ nm and a total drawing distance of 1600 $\mu \text{m}$ (200 $\mu {\rm m}\,\times \,8$ cycles) are drawn in parallel within the 50 s in contact and vector scan modes. Furthermore, eight sets of multiscale pattern with a line width from 100 nm to several micrometers and a drawing area of $100~\mu \text{m} \times 50\mu \text{m}$ , corresponding to a total distance of 400 mm (50 ${\rm mm}\times 8$ cycles), are stably drawn within 30 min in contact- and raster-scan modes. Better resolution is achieved by increasing the scan rate, as well as by reducing the bias voltage and the environmental humidity. Thus, line patterns with a width of $\sim 50$ nm are drawn. [2014-0245]