Nanolithography

Nanolithography

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).

Optical lithography

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

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.

Introduction of Nanotechnology

In the early 20th century, Henry Ford built a car manufacturing plant on a 2,000-acre tract of land along the Rouge River in Michigan. Built to mass-produce automobiles more efficiently, the Rouge housed the equipment for developing each phase of a car, including blast furnaces, a steel mill and a glass plant. More than 90 miles of railroad track and conveyor belts kept Ford's car assembly line running. The Rouge model was lauded as the most efficient method of production at a time when bigger meant better.

The size of Ford's assembly plant would look strange to those born and raised in the 21st century. In the next 50 years, machines will get increasingly smaller -- so small that thousands of these tiny machines would fit into the period at the end of this sentence. Within a few decades, we will use these nanomachines to manufacture consumer goods at the molecular level, piecing together one atom or molecule at a time to make baseballs, telephones and cars. This is the goal of nanotechnology.