Using low-contrast negative-tone PMMA at cryogenic temperatures for 3D electron beam lithography

We report on a 3D electron beam lithography (EBL) technique using polymethyl methacrylate (PMMA) in the negative-tone regime as a resist. First, we briefly demonstrate 3D EBL at room temperature. Then we concentrate on cryogenic temperatures where PMMA exhibits a low contrast, which allows for strai...

Full description

Saved in:
Bibliographic Details
Published in:Nanotechnology 2016-05, Vol.27 (19), p.195301-195301
Main Authors: Schnauber, Peter, Schmidt, Ronny, Kaganskiy, Arsenty, Heuser, Tobias, Gschrey, Manuel, Rodt, Sven, Reitzenstein, Stephan
Format: Article
Language:English
Subjects:
3D lithography
Cryogenic temperature
Damage
Electron beam lithography
Evolution
low-temperature electron-beam lithography
microlenses
Microstructure
Patterning
PMMA
Polymethyl methacrylates
semiconductor nanostructures
Three dimensional
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We report on a 3D electron beam lithography (EBL) technique using polymethyl methacrylate (PMMA) in the negative-tone regime as a resist. First, we briefly demonstrate 3D EBL at room temperature. Then we concentrate on cryogenic temperatures where PMMA exhibits a low contrast, which allows for straightforward patterning of 3D nano- and microstructures. However, conventional EBL patterning at cryogenic temperatures is found to cause severe damage to the microstructures. Through an extensive study of lithography parameters, exposure techniques, and processing steps we deduce a hypothesis for the cryogenic PMMA's structural evolution under electron beam irradiation that explains the damage. In accordance with this hypothesis, a two step lithography technique involving a wide-area pre-exposure dose slightly smaller than the onset dose is applied. It enables us to demonstrate a >95% process yield for the low-temperature fabrication of 3D microstructures.
ISSN:0957-4484
1361-6528
DOI:10.1088/0957-4484/27/19/195301