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Nanomedicine
Molecular self-assembly
Molecular electronics
Scanning probe microscopy
Nanolithography
Molecular nanotechnology
Nanomaterials
Nanomaterials Fullerene
Carbon nanotubes
Nanotube membranes
Fullerene chemistry
Applications Popular culture
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Nanoparticles Quantum dots
Colloidal gold Colloidal silver
Molecular nanotechnology
Molecular assembler
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Nanorobotics Grey goo
K. Eric Drexler
Engines of Creation
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Nanolithography — or lithography at the nanometer scale — refers to the fabrication of nanometer-scale structures, meaning patterns with at least one lateral dimension between the size of an individual atom and approximately 100 nm. Nanolithography is used during the fabrication of leading-edge semiconductor integrated circuits or nanoelectromechanical systems (NEMS).

As of 2007, nanolithography is a very active area of research in academia and in industry.

Optical lithography

Main article: Photolithography


Optical lithography, which has been the predominant patterning technique since the advent of the semiconductor age, is capable of producing sub-100-nm patterns with the use of very short wavelengths (currently 193 nm). Optical lithography will require the use of liquid immersion and a host of photomask enhancement technologies (phase-shift masks (PSM), optical proximity correction (OPC)) at the 32 nm node. Most experts feel that traditional optical lithography techniques will not be cost effective below 30 nm. At that point, it may be replaced by a next-generation lithography (NGL) technique.

Other nanolithography techniques

X-ray lithography can be extended to an optical resolution of 15 nm by using the short wavelengths of 1 nm for the illumination. This is implemented by the proximity printing approach. The technique is developed to the extent of batch processing. The extension of the method relies on Near Field X-rays in Fresnel diffraction: a clear mask feature is "demagnified" by proximity to a wafer that is set near to a "Critical Condition". This Condition determines the mask-to-wafer Gap and depends on both the size of the clear mask feature and on the wavelength. The method is simple because it requires no lenses.

A method of pitch resolution enhancement which is gaining acceptance is double patterning. This technique increases feature density by printing new features in between pre-printed features on the same layer. It is flexible because it can be adapted for any exposure or patterning technique. The feature size is reduced by non-lithographic techniques such as etching or sidewall spacers.

Work is in progress on an optical maskless lithography tool. This uses a digital micro-mirror array to directly manipulate reflected light without the need for an intervening mask. Throughput is inherently low, but the elimination of mask-related production costs - which are rising exponentially with every technology generation - means that such a system might be more cost effective in the case of small production runs of state of the art circuits, such as in a research lab, where tool throughput is not a concern.
  • The most common nanolithographic technique is Electron-Beam Direct-Write Lithography (EBDW), the use of a beam of electrons to produce a pattern — typically in a polymeric resist such as PMMA.
  • Extreme ultraviolet lithography (EUV) is a form of optical lithography using ultrashort wavelengths (13.5 nm). It is the most popularly considered NGL technique.
  • Charged-particle lithography, such as ion- or electron-projection lithographies (PREVAIL, SCALPEL, LEEPL), are also capable of very-high-resolution patterning.
  • Nanoimprint lithography (NIL), and its variants, such as Step-and-Flash Imprint Lithography, LISA and LADI are promising nanopattern replication technologies. This technique can be combined with contact printing.
  • Scanning probe lithography (SPL) is a promising tool for patterning at the deep nanometer-scale. For example, individual atoms may be manipulated using the tip of a scanning tunneling microscope (STM). Dip-Pen Nanolithography (DPN) is the first commercially available SPL technology based on atomic force microscopy.
  • The furthest developed NGL remains X-ray lithography which is extensible to 15 nm resolution by use of "demagnification" in the Near Field.
  • Chemomechanical Surface Patterning using an atomic force microscope is another type of nanolithography. [1]

Bottom-up Methods

  • Nanosphere lithography uses self-assembled monolayers of spheres (typically made of polystyrene) as evaporation masks. This method has been used to fabricate arrays of gold nanodots with precisely controlled spacings.[2]
It is possible that molecular self-assembly methods will take over as the primary nanolithography approach, due to ever-increasing complexity of the top-down approaches listed above. Self-assembly of dense lines less than 20 nm wide in large pre-patterned trenches has been demonstrated (see e.g., D. Sundrani et al., Langmuir, vol. 20, 5091-5099 (2004)). The degree of dimension and orientation control as well as prevention of lamella merging still need to be addressed for this to be an effective patterning technique. The important issue of line edge roughness is also highlighted by this technique.

See also

References

1. ^ R. C. Davis et al., Chemomechanical Surface Patterning and Functionalization of Silicon Surfaces Using an Atomic Force Microscope, Appl. Phys. Lett. 82 (5): 808-810 (2003). Related article
2. ^ A. Hatzor-de Picciotto, A. D. Wissner-Gross, G. Lavallee, P. S. Weiss (2007). "Arrays of Cu(2+)-complexed organic clusters grown on gold nano dots". Journal of Experimental Nanoscience 2: 3-11. 

External links

Nanotechnology refers broadly to a field of applied science and technology whose unifying theme is the control of matter on the atomic and molecular scale, normally 1 to 100 nanometers, and the fabrication of devices within that size range.
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Although nanotechnology is a relatively recent development in scientific research, the development of its central concepts happened over a longer period of time.

Pre-Nanotechnology


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Nanopollution is a generic name for all waste generated by nanodevices or during the nanomaterials manufacturing process. This kind of waste may be very dangerous because of its size. It can float in air the and might easily penetrate animal and plant cells causing unknown effects.
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Drug delivery

The overall drug consumption and side-effects can be lowered significantly by depositing the active agent in the morbid region only and in no higher dose than needed. This highly selective approach reduces costs and human suffering.
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This is a list of organizations involved in nanotechnology.

Government

  • EU Seventh Framework Programme and Action Plan for Nanosciences and Nanotechnologies 2005-2009 http://cordis.europa.eu/nanotechnology/actionplan.htm
  • U.S.

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This is a list of references and appearances of Nanotechnology in works of fiction.

Films

  • Agent Cody Banks: Dr. James Corner built nanobots for ERAS.
  • : "Micro-devices", that can be injected into a victim to kill them at will.

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This page aims to be a heierarchical directory of all topics related to nanotechnology. Items marked with an asterisk (*) appear more than once in the list.

General

Main article: Nanotechnology

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Nanomedicine is the medical application of nanotechnology. It covers areas such as nanoparticle drug delivery and possible future applications of molecular nanotechnology (MNT) and nanovaccinology.
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Molecular self-assembly is the assembly of molecules without guidance or management from an outside source.There are two types of self-assembly, intramolecular self-assembly and intermolecular self-assembly.
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Molecular electronics (sometimes called moletronics) is an interdisciplinary theme that spans physics, chemistry, and materials science. The unifying feature of this area is the use of molecular building blocks for the fabrication of electronic components, both passive (e.
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Scanning probe microscopy (SPM) is a new branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. An image of the surface is obtained by mechanically moving the probe in a raster scan of the specimen, line by line, and recording the
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Molecular Nanotechnology


Molecular assembler
Mechanosynthesis
Nanorobotics
Grey goo
K. Eric Drexler
Engines of Creation
See also:
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Nanomaterials is the study of how materials behave when their dimensions are reduced to the nanoscale. It can also refer to the materials themselves that are used in nanotechnology.
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fullerenes, discovered in 1985 by Robert Curl, Harold Kroto and Richard Smalley at the University of Sussex and Rice University, are a family of carbon allotropes named after Richard Buckminster Fuller and are sometimes called buckyballs.
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Carbon nanotubes (CNTs) are allotropes of carbon. A single-walled carbon nanotube (SWNT) is a one-atom thick sheet of graphite (called graphene) rolled up into a seamless cylinder with diameter on the order of a nanometer.
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Nanotube membranes are films composed of open-ended nanotubes that are oriented perpendicularly to the surface of an impermeable film matrix like the cells of a honeycomb. Fluids and gas molecules may pass through the membrane en masse.
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Fullerene chemistry is a field of organic chemistry devoted to the chemical properties of fullerenes.[1][2][3]. Research in this field is driven by the need to functionalize fullerenes and tune their properties.
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Carbon nanotubes have many potential applications, here is a list of some of the most important:

Structural

  • clothes: waterproof tear-resistant cloth fibers
  • combat jackets

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The following is a list of references to fullerenes in popular culture.

Fine Art



Physicist-turned-artist Julian Voss-Andreae has created several sculptures symbolizing wave-particle duality in Buckminsterfullerenes[1].
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Timeline of carbon nanotubes:

1952

  • Radushkevich and Lukyanovich publish a paper in the Russian Journal of Physical Chemistry showing hollow graphitic carbon fibers that are 50 nanometers in diameter.

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Diamond is one of the best known allotropes of carbon, whose hardness and high dispersion of light make it useful for industrial applications and jewelry. Diamond is the hardest known natural mineral, which makes it an excellent abrasive and makes it hold polish and lustre
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nanoparticle (or nanopowder or nanocluster or nanocrystal) is a microscopic particle with at least one dimension less than 100 nm. Nanoparticle research is currently an area of intense scientific research, due to a wide variety of potential applications in
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A quantum dot can be made from a semiconductor nanostructure that confines the motion of conduction band electrons, valence band holes, or excitons (bound pairs of conduction band electrons and valence band holes) in all three spatial directions.
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Colloidal gold, also known as "nanogold", is a suspension (or colloid) of sub-micrometre-sized particles of gold in a fluid--usually water. The liquid is usually either an intense red colour (for particles less than 100 nm), or a dirty yellowish colour (for larger
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Colloidal silver is a colloid of silver particles in water. It has antimicrobial properties and was, in the past, used on external wounds and burns to prevent infection. Some alternative-health practitioners claim that it is a beneficial nutritional supplement.
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A molecular assembler as defined by K. Eric Drexler is a "proposed device able to guide chemical reactions by positioning reactive molecules with atomic precision." He also introduced a related term, "molecular manufacturing," which he defined as the programmed "chemical synthesis
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Mechanosynthesis in chemistry is any chemical synthesis that takes place by mechanical forces alone.

Introduction

In conventional chemical synthesis or chemosynthesis, reactive molecules encounter one another through random thermal motion in a liquid or vapor.
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Nanorobotics is the technology of creating machines or robots at or close to the scale of a nanometres (10-9 metres). More specifically, nanorobotics refers to the still largely hypothetical nanotechnology engineering discipline of designing and building nanorobots.
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Grey goo is a hypothetical end-of-the-world scenario involving molecular nanotechnology in which out-of-control self-replicating robots consume all living matter on Earth while building more of themselves (a scenario known as ecophagy).
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Kim Eric Drexler (born April 25, 1955 in Oakland, California) is an American engineer best known for popularizing the potential of molecular nanotechnology (MNT), from the 1970s and 1980s.
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