Nickel nanostructures have found widespread application as both functional components, e.g. in magnetic systems, and as part of the lithographic pattern transfer process as etch masks, EUV mask absorbers, and imprint templates. Electron-beam induced etching of nickel is highly desirable for the repair and editing of masks and templates with high resolution and without substrate damage. However, there are no known gas-phase reactants that produce volatile nickel products under e-beam irradiation. Here we report the successful local etching of nickel by a focused electron beam in an environmental scanning electron microscope using a liquid reactant, aqueous sulfuric acid. Sulfuric acid did not spontaneously etch nickel under ESEM conditions, but nickel was etched in areas exposed to the electron beam. Etching parameters such as dose, refresh time, and addition of a surfactant were investigated. The extent of the etch increases with dose before terminating at sub-micron feature sizes. The etch resolution improves with the addition of surfactant. This approach enables local nickel patterning with complete film removal but without damaging underlying layers. With further refinement, the process may enable nickel absorber repair and editing and remove a significant obstacle to the use of nickel in EUV lithography.
|Published - Oct 16 2020
Bibliographical noteFunding Information:
This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1538650 and the Ministry of Higher Education and Scientific Research in Iraq. This work was performed in part at the University of Kentucky Center for Nanoscale Science and Engineering, the University of Kentucky Electron Microscopy Center, and the University of Louisville Micro and Nano Technology Center, members of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (ECCS-1542164). This work used equipment supported by National Science Foundation Grant No. CMMI-1125998.
© 2020 IOP Publishing Ltd.
- 3D nanoprinting
- electron beam induced etching
- environmental scanning electron microscopy
- extreme ultraviolet (EUV) lithography mask repair
- liquid phase focused electron-beam induced processing
- nickel etching
- two-photon lithography
ASJC Scopus subject areas
- Chemistry (all)
- Materials Science (all)
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering