Fabrication of Nanopatterns on Silicon Surface by Combining AFM-Based Scratching and RIE Methods

Abstract

This study presents an atomic force microscope (AFM)-based scratching combined with reactive ion etching (RIE) method to fabricate nanopatterns on the silicon surface. All AFM-based scratching processes are performed on the polymethylmethacrylate (PMMA) film to create features in order to protect the AFM tip from wearing and enlarge its life time. Two types of resist films are selected for the RIE process. One is only PMMA thin-film resist, and the other one contains two-layer thin-film resist which are PMMA and aluminum thin films. The nanopatterns on the silicon after etching using RIE with these two types of resist film are compared. Results show that when using PMMA film, the width of the nanopattern on silicon is larger than on the PMMA film, and the material pile-ups formed during the scratching process cannot be considered as a resist. On the contrary, the aluminum thin films can improve the quality of the transfer. It indicates that the thin-film resist with bilayers can guarantee the transfer accuracy of the features, which can expand the application of the AFM tip-based scratching technique.