What is Nanolithography – Definition
Nanotechnology has given birth to many useful sub technologies, one of them is the Nanolithography. It is a science which deals with structure at microscopic level for detecting, writing, printing and communicating their characteristics to concerned parts.
It refers to the fabrication of nanometer structures and patterns in diverse dimensions. It includes different techniques for modifying semiconductor chips at the atomic level for Integrated Fabrications (ICs Fabrications).
How Nanolithography works?
Nanolithography is used in the many fields of applications, it is a branch of nanotechnology which is used for further fabrications of nanometer materials and molecules. It is used during the integration of edge semiconductors, integrated nanocircuitry or nanoelectromechanical systems.Two of most important instruments used in the nanolithography processing are
- Scanning Probe Microscope (SPM)
- Atomic Force Microscope (ATM).
The Scanning probe microscope permits the surface viewing in advanced detail without modifying it and both SPM and the ATM could be engaged to write, or print on a surface in individual atom direction.
Types of Nanolithography
Nanolithography has many a type according to the area of work in which it is used. Some of them are listed below with brief description.
Optical lithography, is a technique for patterning the various surfaces and have the capability for producing sub patterns up-to to 100 nm with minor wave lengths. Optical nanolithography requires the use of liquid immersion and resolution host.Most experts feel that optical nano lithography techniques are most cost effective then traditional methods of lithography.
Another type of nanolithogrphy is the x ray nanolithography which is quite different from traditional X-ray lithography.It has the ability to improve and extend optical resolution of 15 nm by using the short wavelengths of 1 nm for the illumination. This is performed by printing approach and is used for batch processing.
1)Electron Beam Direct –Write Lithography
The most famous nanolithography meothod is electron beam direct Write lithography(EBDW) technique, which makes use of electron beam to draw a pattern.It is mostly used in the polymers to obtain different patterns of polymeric structures
2)Extreme ultraviolet lithography
Extreme ultra voilet wave lithography is commonly called EUV.It is type of optical lithography which makes use of highly active light beam such as ultra voilet radiations and these are used to produce and measure the wavelengths of different kind of materials.It is also known as NGL method.
This technique also has the capability of producing high resoultion patterns and deals with the broad beam of ions and can also produce patterns having very high resolution.Broad beam of ion have highly charged particles which when hit the surface designs a specific desired pattern.
Neutral Particle Lithography
Neutral paricle lithography is another technique which is also know as NPL.It make use of wide beam of active neutral particles for producing high resolution patterns and images.
Atomic Force Microscopic Nanolithography(AFM)
Atomic Force Microscpic Nanolithography is a method having chemical and mechanical properties and is commony called as chemomechanical surface pattering method.This technique uses atomic force microscope for the image generation.
Molecular assembly Methods
There is a possibility that molecular sefl assembly approaches can dominate the basic nanolithography techniques in near future, because of high complexity of top-down approaches.Self assembly of deep pattern lines having width less than 20 nm and with the large pattern streches can be demostrated with the help of molecular assembly technqiues.One of the important issue of edge thickness and irregular shape is highlighted by molecular self assembly techniques.It is considered to be the most effective technique till now but dimensional changes,directions and molecular merging is still required to be explored even with the high resolution patterns produced by the self assembly techniques.