What is a semiconductor chip, and why do your phone and car depend on one? It’s a tiny circuit built on silicon, packed with transistors that switch electrical signals on and off.
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| Item | Value |
|---|---|
| Purity of the silicon ingots fabs produce | 99.9999% pure |
| Year the transistor was invented at Bell Labs | 1947 |
| Semiconductor units manufactured in 2021 | 1.15 trillion units |
| Longest quoted production time, design to production | up to 26 weeks |
| Lithography and etching cycles for one chip | hundreds of times |
These figures come from Computerworld and Nanotronics. They can change, so check the sources before you rely on them.
What makes silicon a semiconductor?
Silicon is a natural semiconductor: under some conditions it conducts electricity, and under others it acts as an insulator. Adding impurities, a process called doping, alters its electrical properties, according to Computerworld.
That flexibility makes silicon an ideal material for transistors, which are simple devices that amplify electrical signals. Transistors can also act as switches, and combinations of them represent the Boolean operators “and,” “or” and “not.” The transistor itself was invented at Bell Labs in 1947.
Silicon is not the only option. Manufacturers typically use pure elements like silicon or germanium as semiconducting materials, as Nanotronics notes in its manufacturing guide.
Which kinds of chips exist and why they matter
A chip is an integrated circuit, and fabs turn raw silicon wafers into integrated circuits such as microchips. TechTarget describes a fab as a manufacturing plant built for exactly that job.
Several types of chip are made today:
- Microprocessors are logic chips that perform the computations inside most commercial computers.
- Memory chips store information.
- Digital signal processors convert between analog and digital signals.
- Application-specific integrated circuits are special-purpose chips used in things such as cars and appliances.
Such chips end up in a wide range of devices, including computers, solid-state drives, mobile phones, televisions and automobiles. The scale is huge: the microelectronics industry manufactured a record 1.15 trillion semiconductor units in 2021, according to Nanotronics.
Chips are the hardware underneath many fast-moving topics. If you’re curious about the software side, read our explainer on what is artificial intelligence. For the networking side, see our guide on how does 5g work.
How a chip is made, step by step
Chips are made in multibillion-dollar fabrication plants called fabs. Fabs melt and refine sand to produce 99.9999% pure single-crystal silicon ingots, and saws slice those ingots into wafers about as thick as a dime. Each wafer is then used to build multiple chips, per Computerworld.
The fabrication process includes three main areas: wafer creation, circuit construction and packaging. In practice, the circuit-building part runs through a repeating sequence:
- Prepare the wafer. The silicon crystal is sliced into thin wafers and polished smooth, because even slight contamination can cause defects.
- Coat with photoresist. A light-sensitive material goes on the wafer surface to make it suitable for circuit printing.
- Expose the pattern. Ultraviolet light shines through a patterned mask, printing the circuit design on the coated wafer.
- Etch. Excess material is removed either by wet etching with chemical solutions or by dry etching with gases or plasma.
- Implant ions. Impurities such as arsenic or phosphorous ions are embedded to give the silicon its semiconducting properties.
- Add metal connections. Metal circuits link the electronic elements, and the most common materials are aluminum and copper.
- Test, dice and package. The wafer is separated into individual chips, which are placed onto a substrate through bonding.
The pattern-and-etch routine is called photolithography, which TechTarget calls the most common method used to manufacture semiconductor microchips. Photolithography with different masks, followed by more etching and doping, can be repeated hundreds of times for the same chip, so each pass adds complexity to the circuit.
Why does the clean room matter?
Every fab includes a clean room. Its environment is carefully controlled to eliminate dust and vibrations and to keep the temperature and humidity within a specific narrow range, as TechTarget explains.
The reason is simple: contamination can damage products and hurt overall yield. Yield is the percentage of functional chips relative to all the chips on a single wafer, so a higher yield means more value from each wafer.
That is why testing happens before packaging. In electrical die sorting, the wafer touches a probe card that consists of numerous tiny pins, and the electrical signals reveal defective chips. Good chips go into supporting packages that let them plug into circuit boards, while bad chips are marked and discarded.
What makes chipmaking hard and slow
Making a chip is a long, exacting job. The entire process can take up to 26 weeks from design to production, according to Nanotronics, a company that sells inspection technology to manufacturers.
Its guide lists the main challenges manufacturers face:
- Product quality, which gets harder as chips become more advanced and demand grows.
- Defects, which can arise from assembling through testing and are hard to spot given each chip’s size and number of layers.
- Cost, which is rising as new technologies emerge and shortages occur.
- Equipment, since manufacturers must keep up with new tools and technologies.
- Time, because even minor problems can ruin an entire batch of chips.
Those pressures explain why a single fab is such a large investment, and why a shortage in one part of the chain can ripple through the products you buy.
Frequently asked questions
What is a semiconductor chip in simple terms?
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It is a small piece of silicon carrying an integrated circuit, made of transistors that amplify signals or act as on/off switches. Together, those switches can perform the computations and storage that devices need.
Is a microchip the same as an integrated circuit?
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Mostly, yes. TechTarget describes fabs as turning raw silicon wafers into integrated circuits, such as microchips, so the terms are commonly used for the same thing.
Why is silicon used for chips?
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Silicon is a natural semiconductor that can conduct or insulate depending on conditions. Doping lets manufacturers alter its electrical properties, which suits it to making transistors.
How long does it take to make a chip?
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One manufacturing guide says the entire process can take up to 26 weeks, from design to production. Actual timing varies, so treat that as an upper figure from one source.
What happens to faulty chips?
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Each chip on the wafer is tested for correct performance. Good chips are packaged, and bad chips are marked and discarded.
