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Photolithography

Also Known As Optical Lithography
Electrical Engineering

Photolithography transfers a geometric pattern onto a light-sensitive chemical coating, called a photoresist, on a substrate, usually a silicon wafer, by exposing it to light through a patterned mask. The exposed or unexposed resist is then chemically developed away, leaving a patterned mask that guides subsequent etching, doping or deposition steps. Repeated many times with different masks, it is the core patterning method behind modern integrated circuit fabrication. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/

Facts
Disputed
Origin Year
1957 2
Bell Telephone Laboratories applied photolithographic patterning to semiconductor manufacture in the mid-to-late 1950s; the exact priority between early adopters at Bell Labs and, later, Fairchild Semiconductor is not settled at the level of a single event, though the period is well attested.
Core Principle
Exposing a photoresist-coated substrate to light through a patterned mask, then chemically developing the resist to leave a precise pattern that guides etching or deposition. 1
Photolithography
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Connections

Associated With

Nanotechnology, Fields
Semiconductor Doping, Methods

Photolithography and doping are paired steps repeated many times in integrated circuit fabrication.

Silicon, Materials

Photolithography patterns circuits onto silicon wafers.

The Integrated Circuit, Inventions

Photolithographic patterning is the core method that makes modern integrated circuit fabrication possible.

In Field

Sources
1. Photolithography (Wikipedia)
Wikipedia contributors, Wikimedia Foundation
  • Introduction section, exposure and development
    A photomask that contains the desired pattern is then placed over the photoresist. Light is shone through the photomask, exposing the photoresist in certain areas. The exposed areas undergo a chemical change, making them either soluble or insoluble in a developer solution. After development, the pattern is transferred onto the sample through etching.
  • lead sentence
    Photolithography (also known as optical lithography) is a process that involves using light to transfer a pattern onto a photoresist.
View the Source
2. A History of Technology
Charles Singer, E. J. Holmyard, A. R. Hall and Trevor I. Williams, editors, Oxford University Press, 1954View the Source
Frequently Asked Questions

How does photolithography create a pattern on a silicon wafer?

Light through a mask patterns a photoresist, which then guides etching, doping or deposition.

The wafer is coated with a light-sensitive chemical called a photoresist and exposed to light through a patterned mask. The exposed or unexposed resist is then chemically developed away, leaving a patterned mask that guides later etching, doping or deposition steps. Repeated many times with different masks, this is the core patterning method behind modern integrated circuit fabrication.
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