Background
Microchips are examples of integrated circuits—flat pieces of semiconducting material whose surfaces contain billions of circuit components wired together.
ICs can be smaller than the width of a pencil point, allowing the components to quickly transmit electrical signals between one another with minimal energy loss and delay (watch microscopic tour).
Their ability to be reliably mass-produced has made ICs the backbone of all modern electronics, responsible for data processing, memory storage, signal transmission, and power management (types of ICs).
Over 427 billion ICs were shipped worldwide in 2022, with revenue expected to reach $583B in 2025.
History
The invention of ICs was driven by computer engineers seeking solutions to the “tyranny of numbers,” where computers built to solve numerical problems had become so large and complex that their maintenance and operation offset computational gains.
In 1945, the first electronic computer, the ENIAC, performed calculations related to the hydrogen bomb using 18,000 vacuum tubes—on-off switches representing the binary code of ones and zeros. However, a tube would fail every other day, slowing down monthslong computations.
The breakthrough came two years later with the invention of transistors. These devices are made of layers of semiconducting material (e.g., silicon), which can be controlled to switch between conducting and insulating against the flow of electricity (watch explainer).
For over a decade, researchers investigated integration—how to place all circuit components and their interconnections on a single piece of semiconductor to simplify assembly.
Texas Instruments unveiled a germanium-based IC at the Institute of Radio Engineers’ 1959 trade show, but it was largely overshadowed by a radar-based, hands-free driving system (1440 Topics: Self-Driving Cars).
Later that year, Fairchild Semiconductor developed the first silicon-based IC, which could be mass-produced. Spurred on by the Space Race, NASA purchased an estimated 60% of all manufactured ICs through 1965 for the Apollo Guidance Computer (1440 Topics: Apollo Program).
Manufacturing
Today’s ICs are created from a complex series of chemical and physical processes that use light to construct circuit components from purified sand (watch visualization).
First, quartz rocks of high-silicon purity are mined and ground into sand. The sand is melted and processed to remove impurities before the remaining molten silicon is exposed to a seed crystal. Molten silicon slowly solidifies onto the seed, forming a cylindrical crystal that is removed and polished.
Crystals are cut into wafers and then exposed to oxygen to form a silicon dioxide layer, followed by a polysilicon layer and a light-sensitive chemical coating called a photoresist. Through photolithography, ultraviolet light is shined through a mask above the layers, creating a pattern of exposed and unexposed regions on the photoresist that serve as the blueprint for that layer’s circuitry (watch explainer).
Exposed or unexposed regions are chemically washed away, creating valleys within the layers. In a process known as doping, phosphorus or boron is added to the valleys, producing the conducting and insulating regions of transistors.
Everything is covered in silicon dioxide before ceramic particles smooth the excess and flatten the top layer. After another photoresist layer, the steps repeat multiple times using different masks and chemicals (e.g., aluminum for connections between components).
Wafers can take up to four months to manufacture before being cut into ICs with dozens of layers.
Future
ICs are expected to become more prevalent with the growth of data centers, AI, and the Internet of Things.
Because ICs can house dozens of kilometers of wiring between circuit components, substantial heat is generated from electrical flow—enough to boil water—which can degrade and damage components. To improve performance, new cooling techniques and alternative materials, including flexible semiconducting carbon nanotubes, are being researched.
Quantum ICs will likely become more common and involve more particles as quantum computing progresses (1440 Topics: Quantum Computing).
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