Glasgow has two commercial Vistec VB6 and EPBG5 electron beam lithography tools, 30 years experience of electron beam lithography and holds world records for the smallest wire fabricated by electron beam lithography (3 nm width) and the best layer-to-layer alignment of any technique (0.46 nm rms).
The James Watt Nanofabrication Centre is one of the few places in the world with sub-10 nm single line capability and the appropriate dry etch and metal deposition processes to allow sub-10 nm features to be fabricated and integrated into devices.
We have sub-5 nm capability for single line lithography and have signficant experience of a variety of resist including polymethylmethacrylate (PMMA), hydrogen silsesquioxane (HSQ), ZEP, UVIII and NEB.
Both tools have laser interferometry stage position measurement allowing stitching of fields with sub-1 nm precision using proprietary techniques and the VB6 has an ultra-wide 1.3 mm field. We have a number of proprietary techniques to allow small features to be produced and significant experience of minimising tilt, stitching errors and proximity effects in designs.
Access to the tools can be achieved through collaborative projects (e.g. EPSRC and EC), the EPSRC III-V National Facility and commercially through Kelvin Nanotechnology Ltd..
Download overview of electron beam lithography capability.
Demonstrated nanofabrication examples can be found here and also at the bottom of this page.
Vistec VB6 UHR EWF electron beam lithography tool
- Maximum substrate / wafer size of 200 mm
- Gaussian beam step and exposure writing strategy
- Thermal field emission gun with 50 keV and 100 keV operation
- Minimum spot size < 4 nm
- Demonstrated single lines down to < 5 nm using HSQ resist
- 0.46 nm rms layer-to-layer alignment
- Extra wide field of 1.3 mm at both 50 and 100 keV
- Laser interferometer stage with 0.62 nm resolution
- 50 MHz pattern generator
- Full automated alignment
- Multi-substrate load lock - we run up to 4000 hours of pattern writing per annum
Vistec EBPG5 HR 100 electron beam lithography tool
- Maximum substrate / wafer size of 150 mm
- Gaussian beam step and exposure writing strategy
- LaB6 filament and 20 keV, 50 keV and 100 keV operation
- 10 MHz pattern generator
- Writing field sizes of 560 x 560 µm at 100 keV and 800 x 800 µm at 50 keV
- Laser interferometer stage with 5 nm resolution
- Multi-substrate load lock
Electron Beam Lithography Demonstrated Capability
2.5 nm Isolated HSQ Resist Lines Written by Electron Beam Lithography
D.S. MacIntyre and S. Thoms "Comparison of hydrogen silsesquioxane development methods for sub-10 nm electron beam lithography using accurate linewidth inspection" J. Vac. Sci. Technol. B 29, 06F307 (2011): doi:10.1116/1.3634020
The Smallest Electron Beam Lithography Metal Pattern of 3 nm
D.R.S. Cumming et al. "Fabrication of 3 nm wires using 100 keV electron beam lithography and poly(methyl methacrylate) resist" Appl. Phys. Lett. 68, 322 (1996): doi:10.1063/1.116073
Sub 10 nm Electron Beam Lithography
S. Thoms and D. S. Macintyre "Linewidth metrology for sub-10-nm lithography" J. Vac. Sci. Technol. B 28, C6H6 (2010): doi:10.1116/1.3505129
Picometre Layer-to-layer Alignment
K.E. Docherty et al. "Improvements to the alignment process in a commercial vector scan electron beam lithography tool" Microelec. Eng. 85, 761 (2008): doi:10.1016/j.mee.2008.01.081
Robust Correlation Based Layer-to-layer Alignment
K.E. Docherty et al. "High robustness of correlation-based alignment with Penrose patterns to marker damage in electron beam lithography" Microelec. Eng. 86, 532 (2009): doi:10.1016/j.mee.2008.11.037
10 nm T-gate HEMTs
S. Bentley et al. "Two methods for realising 10 nm T-gate lithography" Microelec. Eng. 86, 1067 (2009): doi:10.1016/j.mee.2008.12.029
1 nm Gaps Between Metal Electrodes: Beating the Proximity Effect
P. Steinmann and J.M.R. Weaver "Fabrication of sub-5 nm gaps between metallic electrodes using conventional lithographic techniques" J. Vac. Sci. Technol. 22(6), 3178 (2005): doi:110.1116/1.1808712
Large Area Superhydrophobic and Hydrophilic Nanopatterns
E. Martines et al. "Superhydrophobicity and Superhydrophilicity of Regular Nanopatterns" Nano Letters 5, 2097 (2005): doi:10.1021/nl051435t
10 mm Long Low Loss Silicon Waveguides (loss < 0.9 dB/cm)
M. Gnan et al. "Fabrication of low loss photonic wires in silicon-on-insulator using hydrogen silsesquioxane electron-beam resist" Elec. Lett. 44, 115 (2008): doi:10.1049/el:20082985
Tilt-corrected Stitching
S. Thoms and D.S. Macintyre "Tilt-corrected stitching for electron beam lithography" Microelec. Eng. 84, 793 (2007): doi:10.1016/j.mee.2007.01.127