The planar process is a

manufacturing process Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a ran ...

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. 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 ...

and

thermal oxidation In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer. The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it. The rat ...

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.

Overview

The key concept is to view a circuit in its two-dimensional projection (a plane), thus allowing the use of

photographic processing Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image in ...

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 transis ...

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 Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

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 meeting, Mohamed Atalla presented a paper about the

of PN junctions by

, 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 fab ...

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. The planar process was developed by Jean Hoerni, one of the " traitorous eight", while working at

, with a first patent issued 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 boule. In 1959, Robert Noyce 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, or resistors, 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 EUV light, generated by a tin-based plasma source.

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

Overview

History

Development

See also

References

External links