The planar process is a manufacturing process used in the

semiconductor industry The semiconductor industry is the aggregate of companies engaged in the design and fabrication of semiconductors and semiconductor devices, such as transistors and integrated circuits. It formed around 1960, once the fabrication of semiconduct ...

to build individual components of a

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...

, and in turn, connect those transistors together. It is the primary process by which

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...

integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...

chips are built, and it is the most commonly used method of producing

junctions Junction may refer to: Arts and entertainment * ''Junction'' (film), a 2012 American film * Jjunction, a 2002 Indian film * Junction (album), a 1976 album by Andrew Cyrille * Junction (EP), by Basement Jaxx, 2002 * Junction (manga), or ''Hot ...

during the manufacture of

semiconductor device A semiconductor device is an electronic component that relies on the electronic properties of a semiconductor material (primarily silicon, germanium, and gallium arsenide, as well as organic semiconductors) for its function. Its conductivity li ...

s. The process utilizes the

surface passivation A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. It is the portion or region of the object that can first be perceived by an observer using the senses of sight and touch, and is t ...

and thermal oxidation methods. The planar process was developed at

Fairchild Semiconductor Fairchild Semiconductor International, Inc. was an American semiconductor company based in San Jose, California. Founded in 1957 as a division of Fairchild Camera and Instrument, it became a pioneer in the manufacturing of transistors and of int ...

in 1959. The planar process proved to be one of the most important single advances in semiconductor technology.

Overview

The key concept is to view a circuit in its two-dimensional projection (a plane), thus allowing the use of photographic processing concepts such as film negatives to mask the projection of light exposed chemicals. This allows the use of a series of exposures on a substrate (

) to create

silicon oxide Silicon oxide may refer to either of the following: *Silicon dioxide or quartz, SiO2, very well characterized *Silicon monoxide Silicon monoxide is the chemical compound with the formula SiO where silicon is present in the oxidation state +2. In ...

(insulators) or doped regions (conductors). Together with the use of metallization, and the concepts of

p–n junction isolation p–n junction isolation is a method used to electrically isolate electronic components, such as transistors, on an integrated circuit (IC) by surrounding the components with reverse biased p–n junctions. Introduction By surrounding a transistor ...

and

, it is possible to create circuits on a single silicon crystal slice (a wafer) from a monocrystalline silicon boule. The process involves the basic procedures of

silicon dioxide Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

(SiO₂) oxidation, SiO₂ etching and heat diffusion. The final steps involves oxidizing the entire wafer with an SiO₂ layer, etching contact vias to the transistors, and depositing a covering metal layer over the

oxide An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...

, thus connecting the transistors without manually wiring them together.

History

Development

At a 1958

Electrochemical Society The Electrochemical Society is a learned society (professional association) based in the United States that supports scientific inquiry in the field of electrochemistry and solid-state science and related technology. The Society membership compris ...

meeting,

Mohamed Atalla Mohamed M. Atalla ( ar, محمد عطاالله; August 4, 1924 – December 30, 2009) was an Egyptian-American engineer, physicist, cryptographer, inventor and entrepreneur. He was a semiconductor pioneer who made important contributions to ...

presented a paper about the

of PN junctions by thermal oxidation, based on his 1957 BTL memos. Swiss engineer

Jean Hoerni Jean Amédée Hoerni (September 26, 1924 – January 12, 1997) was a Swiss-American engineer. He was a silicon transistor pioneer, and a member of the " traitorous eight". He developed the planar process, an important technology for reliably fa ...

(one of the "

traitorous eight The traitorous eight was a group of eight employees who left Shockley Semiconductor Laboratory in 1957 to found Fairchild Semiconductor. William Shockley had in 1956 recruited a group of young Ph.D. graduates with the goal to develop and produce ...

") attended the same 1958 meeting, and was intrigued by Atalla's presentation. Hoerni came up with the "planar idea" one morning while thinking about Atalla's device. Taking advantage of silicon dioxide's passivating effect on the silicon surface, Hoerni proposed to make transistors that were protected by a layer of silicon dioxide. This led to the first successful product implementation of the Atalla silicon transistor passivation technique by thermal oxide. Jean Hoerni, while working at

, had first patented the planar process in 1959. Together with the use of metallization (to join together the integrated circuits), and the concept of

(from

Kurt Lehovec Kurt Lehovec (June 12, 1918 – February 17, 2012) was one of the pioneers of the integrated circuit. While also pioneering the photo-voltaic effect, light-emitting diodes and History of the battery#Invention, lithium batteries, he innovated ...

), the researchers at Fairchild were able to create circuits on a single silicon crystal slice (a wafer) from a

monocrystalline silicon Monocrystalline silicon, more often called single-crystal silicon, in short mono c-Si or mono-Si, is the base material for silicon-based discrete components and integrated circuits used in virtually all modern electronic equipment. Mono-Si also ...

boule. In 1959,

Robert Noyce Robert Norton Noyce (December 12, 1927 – June 3, 1990), nicknamed "the Mayor of Silicon Valley", was an American physicist and entrepreneur who co-founded Fairchild Semiconductor in 1957 and Intel Corporation in 1968. He is also credited wit ...

built on Hoerni's work with his conception of an

(IC), which added a layer of metal to the top of Hoerni's basic structure to connect different components, such as transistors,

capacitors A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of a ...

, or

resistors A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active el ...

, located on the same piece of silicon. The planar process provided a powerful way of implementing an integrated circuit that was superior to earlier conceptions of the integrated circuit. Noyce's invention was the first monolithic IC chip. Early versions of the planar process used a

photolithography In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer, to protect ...

process using near-ultraviolet light from a mercury vapor lamp. As of 2011, small features are typically made with 193 nm "deep" UV lithography. Shannon Hill
"UV Lithography: Taking Extreme Measures"
National Institute of Standards and Technology (NIST). As of 2022, the ASML NXE platform uses 13.5 nm extreme ultraviolet (EUV) light, generated by a tin-based plasma source, as part of the

extreme ultraviolet lithography Extreme ultraviolet lithography (also known as EUV or EUVL) is an optical lithography technology used in steppers, machines that make integrated circuits (ICs) for computers and other electronic devices. It uses a range of extreme ultraviolet (EUV) ...

process.

References

External links

* A compendium of articles and other information on the development of

integrated circuits An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...

, including th
development of oxide masking
th

th

and th

* An overview of the steps in fabrication of an integrated circuit from the Nobel Prize website. This is a section of the wor

{{DEFAULTSORT:Planar Process Semiconductor device fabrication Swiss inventions Planes (geometry)

Overview

History

Development

See also

References

External links