Electron Beam Lithography - 123seminarsonly.com

of 39/39
Electron Beam Lithography
  • date post

    29-Nov-2021
  • Category

    Documents

  • view

    3
  • download

    0

Embed Size (px)

Transcript of Electron Beam Lithography - 123seminarsonly.com

Electron Beam LithographyPatterning Techniques
Patterning Techniques
1.OPTICAL LITHOGRAPHY
a) Deep Ultarviolet Lithography b) Extreme Ultraviolet Lithography c) X Rays
2. NANOIMPRINT
Resolution Limits • Proximity
Gap ~ 20-50 μm
Resolution Limits • Projection
Drawbacks:
b) Extreme Ultraviolet Lithography
• Small wavelenght Better resolution
• Difficult to produce
X Rays difficult
Electron Beam Direct Write • An electron gun or
electron source that supplies the electrons.
• An electron column that 'shapes' and focuses the electron beam.
• A mechanical stage that positions the wafer under the electron beam.
• A wafer handling system that automatically feeds wafers to the system and unloads them after processing.
• A computer system that controls the equipment.
Electron Beam Direct Write Types of electron guns • Thermoionic • Field emission
Write-field (WF)
Raith 150 Manual (Nanostructure Physics Dept. KTH) Anders Liljeborg
Specifications, a real example
Raith150 • Beam size  ≤  2nm @
Electron Projection LithographyElectron Beam
• PREVAIL (IBM) 1999
New solutions
• PREVAIL – Larger effective field
1. Important parameters 2. Types of resist 3. Resist limitations
EBL resists
Polymethyl methacrylate (PMMA)
Important parameters Resolution (nm) Sensitivity (C/cm^2)
Resist limitations • Tendency of the resist to swell in
the developer solution.
– Broadens the diameter of the incident electron beam.
– Gives the resist unintended extra doses of electron exposure .
Applications of Electron Beam Lithography
• Research - Nanopatterning on Nanoparticles - Nanowires - Nanopillars - Gratings - Micro Ring Resonators - Nanofluidic Channels
• Industrial / Commercial - Exposure Masks for Optical Lithography - Writing features
Nanopatterning on nanoparticles• Significance
- Photonic Crystals - Quantum Dots - Waveguides
• Electron Beam Lithography - Fine writing at moderate electron energies - 37nm thick lines with 90nm periodicity - 50nm diameter dots with 140nm periodicity
(2003), Patterning of porous Silicon by Electron Beam Lithography, S. Borini, A. M. Rossi, L. Boarino, G. Amato
Nanowires • Applications
- High-Density Electronics (Sensors, Gates in FETs) - Molecular Electronics & Medical/Biological Applications
• EBL with Electrochemical size reduction - High-Resolution Controlled Fabrication - Widths approaching 10nm regime
• Patterning of Films of Gold Nanoclusters with Electron Beam Direct Write Lithography - Sub 50nm wide Nanowires - Controlled thickness at single particle level
Controlled Fabrication of Silicon Nanowires by Electron beam lithography and Electro- chemical size reduction (2005), Robert Juhasz, Niklas Elfstrom and Jan Linnros
Nanometer Scale Petterinng of Langmuir-Blodgett Films of Gold Nanoparticles by Electron Beam Lithography (2001), Martinus H.V Werts, Mathieu Lambert, Jean-Philippe Bourgoin and Mathias Brush
Nanopillars • Significance
• EBL and Reactive Ion Etching - Etched Pillars with 20nm diameter
Nanotechnology using Electron Beam Lithography, Center for Quantum Devices
Gratings • Applications
• Continuous Path Control Writing using EBL - Avoids stitching errors
Nanotechnology using Electron Beam Lithography, Center for Quantum Devices
Micro Ring Resonators • Applciations
- Optical Telecommunication and Networks
Nanotechnology using Electron Beam Lithography, Center for Quantum Devices
Nanofluidic Channels • Significance
- Tubes with inner dimension of 80nm
(2005) A single-step process for making nanofluidic channels using electron beam lithography, J. L. Pearson and D. R. S. Cumming
Industrial Applications
• Writing Features
• Cryo-electric devices • Optoelectronic devices • Quantum structures • Multi-gate Devices • Transport mechanism for semi and superconductor
interfaces • Optical devices • Magnetism • Biological Applications
– Nano-MEMS – Nanofluidics
Future opportunities for electron beam lithography
1. Double gate FinFET devices 2. Single electron transistors 3. Photonic crystals
• Principle
thin body region by two gates
• Fabrication thanks to e-beam
- Low energy (5 keV)
- High resolution organic resist
- Silicon etching
Double gate FinFET devices - Concept
20 nm electron beam lithography and reactive ion etching for the fabrication of double gate FinFET devices (2003), J. Kretz , L. Dreeskornfeld, J. Hartwich, W. Rosner
Nanoscale FinFETs for low power applications (2004), W. Rösner, E. Landgraf, J. Kretz, L. Dreeskornfeld, H. Schäfer, M. Städele,T. Schulz, F. Hofmann, R.J. Luyken, M. Specht, J. Hartwich, W. Pamler, L. Risch
• High performance devices
+ capability of driving a large bitline load
• Low power applications
Double gate FinFET devices – Characteristics & Applications
Nanoscale FinFETs for low power applications (2004), W. Rösner, E. Landgraf, J. Kretz, L. Dreeskornfeld, H. Schäfer, M. Städele,T. Schulz, F. Hofmann, R.J. Luyken, M. Specht, J. Hartwich, W. Pamler, L. Risch
Single electron transistor - Concept • Physic principle
Weak external force to bring an additional electron to a small conductor “island” => Repulsing electric field
• SET concept - Down-scaling - Low power consumption
• Difficulties - Need of very small “islands” because the addition energy must overload the temperature effects
- Polarization in case of impurities => randomness background charge
Single-Electron Devices and Their Applications (1999), Konstantin K. Likharev
Single electron transistor - Fabrication
Fabrication of silicon nanowire structures based on proximity effects of electron-beam lithography (2003), S.F. Hua, W.C. Wengb, Y.M. Wanb
• Classic technique
=> E-beam lithography
Lithography with e-beam, with specific beam current density and dose
Results: single electron charging effect
Polysilicon grain = “islands”
Single electron transistor - Applications
• Single electron spectroscopy
• Replacing MosFET?
• Random access memory - Bit stored in large conductive island (floating gate) - Need of a sense amplifier => association with FET amplifier - Very impressive density: 1011 bit/cm
NO !!!
Photonic crystals - Concept
• => Optical “chips” with waveguides, cavities, mirrors, filters… Example of very compact quantum optical integrated circuit:
• Need of a dielectric or metallic lattice, with adjustable parameters: geometry, dielectric constant…
Three-dimensional photonic crystals operating at optical wavelength region (2000), Susumu Noda
• Creation of the desired lattice
- With e-beam lithography at low beam energy (5keV)
- Negative resist. Ex: SU8-2000, with high refractive index (1,69) and good mechanical stability
• Results
A few mode are allowed to propagate, depending of the photonic crystal parameters
2D photonic crystals
Two-dimensional photonic crystal waveguide obtained by e-beam direct writing of SU8-2000 photoresist (2004), M. De Vittorio, M.T. Todaro, T. Stomeo, R. Cingolani, D. Cojoc, E. Di Fabrizio
3D photonic crystals • Several methods to create the lattice
- Wafer-fusion and alignment
- XRay and e-beam lithography
By wafer-fusion, two-resist process…
Three-dimensional photonic crystals operating at optical wavelength region (2000), Susumu Noda XRay and e-beam lithography of three dimensional array structures for photonics (2004), F. Romanato,
E. Di Fabrizio,M. Galli