Hybrid atomic force/scanning tunneling lithography

Abstract

We present a new technique for performing lithography with scanning probes that has several advantages over standard methods. This hybrid lithography system combines the key features of the atomic force microscope (AFM) and the scanning tunneling microscope (STM) by incorporating two independent feedback loops, one to control current and one to control force. We demonstrate a minimum resolution of 41 nm and nanometer alignment capabilities. This lithography system is capable of writing continuous features over sample topography. Topography is often present in real patterning applications and poses problems for AFM and STM lithography. We report 100 nm resist features patterned over 180 nm of topography created by local oxidation of silicon. The hybrid AFM/STM system is designed as a robust scanning probe lithography tool, capable of high-speed patterning and suited for integrated circuit lithography applications.