Quantum lithography is a type of

photolithography Photolithography (also known as optical lithography) is a process used in the manufacturing of integrated circuits. It involves using light to transfer a pattern onto a substrate, typically a silicon wafer. The process begins with a photosensiti ...

, which exploits non-classical properties of the photons, such as

quantum entanglement Quantum entanglement is the phenomenon where the quantum state of each Subatomic particle, particle in a group cannot be described independently of the state of the others, even when the particles are separated by a large distance. The topic o ...

, in order to achieve superior performance over ordinary classical lithography. Quantum lithography is closely related to the fields of quantum imaging,

quantum metrology Quantum metrology is the study of making high-resolution and highly sensitive measurements of physical parameters using quantum theory to describe the physical systems, particularly exploiting quantum entanglement and quantum Squeezed coherent s ...

, and quantum sensing. The effect exploits the quantum mechanical state of light called the

NOON state In quantum optics, a NOON state or N00N state is a quantum-mechanical many-body entangled state: : , \text \rangle = \frac, \, which represents a superposition of ''N'' particles in mode ''a'' with zero particles in mode ''b'', and vice ver ...

. Quantum lithography was invented at Jonathan P. Dowling's group at JPL, and has been studied by a number of groups. Of particular importance, quantum lithography can beat the classical Rayleigh criterion for the

diffraction Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation ...

limit. Classical

has an

optical imaging Medical optical imaging is the use of light as an investigational imaging technique for medical applications, pioneered by American Physical Chemist Britton Chance. Examples include optical microscopy, spectroscopy, endoscopy, scanning laser o ...

resolution that is limited by the wavelength of light used. For example, in the use of photolithography to mass-produce computer chips, it is desirable to produce smaller and smaller features on the chip, which classically requires moving to smaller and smaller wavelengths (ultraviolet and x-ray), which entails exponentially greater cost to produce the optical imaging systems at these extremely short optical wavelengths. Quantum lithography exploits the

between specially prepared photons in the

and special

photoresist A photoresist (also known simply as a resist) is a light-sensitive material used in several processes, such as photolithography and photoengraving, to form a patterned coating on a surface. This process is crucial in the electronics industry. T ...

s, that display multi-photon absorption processes to achieve the smaller resolution without the requirement of shorter wavelengths. For example, a beam of red photons, entangled 50 at a time in the NOON state, would have the same resolving power as a beam of x-ray photons. The field of quantum lithography is in its infancy, and although experimental proofs of principle have been carried out using the Hong–Ou–Mandel effect, it is considered promising technology.

References

External links

American Institute of PhysicsIntroduction to Quantum LithographyScience News
{{Webarchive, url=https://web.archive.org/web/20080212124314/http://www.sciencenews.org/articles/20011208/bob16.asp , date=February 12, 2008 Quantum information science Lithography (microfabrication)