Selective Pattern Transfer of Nano-Scale Features Generated by FE-SPL in 10 nm Thick Resist Layers

Martin Hofmann

doi:10.11648/j.nano.20180601.12

Abstract

High performance single nanometer lithography is an enabling technology for beyond CMOS devices. In this terms a novel mask- and development-less patterning scheme by using electric field, current controlled Scanning Probe Lithography (FE-SPL) in order to pattern structures on different samples was developed. This work aims to manufacture nanostructures into different resist by using FE-SPL, whereas plasma etching at cryogenic temperatures is applied for an efficient pattern transfer into the bottom Si substrate. The challenge for future quantum devices, generated by SPL and cryogenic etching, is finding a resist that is at most 10 nm in thickness and has a plasma durability high enough for pattern transfer into silicon. As a first step towards future quantum devices the silicon-to-resist selectivity of calixarene, AZ Barli, poly (3-hexylthiophen-2, 5-diyl) and polymethylmethacrylat for the anisotropic cryogenic dry etching process was estimated. A silicon-to-resist selectivity of about 4:1 for each of these resists was found. With these results, nano-scale, highly parallel double line features in silicon for future double patterning were generated.

Highlights

Scaling down of device sizes has been the fundamental strategy for improving the performance and efficiency of nanoelectromechanical devices and systems (NEMS)
Thereby, a Fowler-Nordheim-type electron emission of low energy electrons from a sharp scanning tip is caused by an intense electric field [2]
P3HT and AZ Barli offer similar FieldEmission Scanning Probe Lithography (FE-SPL) resolutions (10 nm half pitch), the best resist for generation of a certain type of nanostructure can be chosen according to their individual properties as conductivity, tone switching and stiffness

Summary

Introduction

Scaling down of device sizes has been the fundamental strategy for improving the performance and efficiency of nanoelectromechanical devices and systems (NEMS). FieldEmission Scanning Probe Lithography (FE-SPL) permits a precise and cost effective fabrication route towards the enabling of new devices as, e.g., single electron transistors [1]. Due to small tip-sample distances and low electron energies FE-SPL can take place in ambient conditions without the requirement for vacuum or special gaseous environments. An atomic force microscopy (AFM) imaging directly after exposure can be done using the same scanning probe, termed ‘active cantilever’. This allows the inspection of the generated features in a closed loop imaging scheme. The closed loop FE-SPL offers single-nanometer manufacturing and has the potential to replace conventional lithography techniques in terms of resolution, direct

Objectives

Methods

Conclusion