Right after the pandemic hit, I bought a new vacuum cleaner. I wanted to step up my housecleaning skills since I knew I’d be home a lot more. I was able to buy mine right away, but friends who wanted new appliances weren’t so lucky. My relatives had to wait months for their new refrigerator to arrive. And it wasn’t just appliances. New cars were absent from dealership lots, while used cars commanded a premium.
What do all these things have in common? Semiconductor chips.
The pandemic disrupted the global supply chain, and semiconductor chips were particularly vulnerable. The chip shortage delivered a wakeup call for our country to make our supply chain more resilient and increase domestic manufacturing of chips, which are omnipresent in modern life.
“To an astonishing degree, the products and services we encounter every day are powered by semiconductor chips,” said Mike Molnar, director of NIST’s Office of Advanced Manufacturing.
Think about your kitchen. Dishwashers have chips that sense how dirty your loads are and precisely time their cleaning cycles to reduce your energy and water bills. Some rice cookers use chips with “fuzzy logic” to judge how long to cook rice. Many toasters now have chips that make sure your bread is perfectly browned.
We commonly think of chips as the “brains” that crunch numbers, and that is certainly true for the CPUs in computers, but chips do all sorts of useful things. Memory chips store data. Digital cameras contain chips that detect light and turn it into an image. Modern TVs produce their colorful displays with arrays of light emitting diodes (LEDs) on chips. Phones send and receive Wi-Fi and cellular signals thanks to semiconductor chips inside them. Chips also abound on the exteriors of homes, inside everything from security cameras to solar panels.
The average car can have upward of 1,200 chips in it, and you can’t make a new car unless you have all of them. “Today’s cars are computers on wheels,” an auto mechanic said to me a few years ago, and his words were never more on point than during the height of the pandemic. In 2021, the chip shortage was estimated to have caused a loss of $110 billion in new vehicle sales worldwide.
The chips in today’s cars are a combination of low-tech, mature chips and high-tech, state-of-the-art processors (which you’ll especially find in electric vehicles and those that have autonomous driving capabilities).
Whether mature or cutting-edge, chips typically need to go through a dizzying series of steps—and different suppliers—before they become finished products. And most of this work is currently done outside this country. The U.S., once a leader in chip manufacturing, currently only has about a 12 percent share in the market.
To reestablish our nation’s leadership in chip manufacturing, Congress recently passed, and President Joe Biden recently signed into law, the CHIPS Act. The CHIPS Act aims to help U.S. manufacturers grow an ecosystem in which they produce both mature and state-of-the-art chips at all stages of the manufacturing process and supply chain, and NIST is going to play a big role in this effort.
The Dirt on Semiconductor Chips
Silicon is the most frequently used raw material for chips, and one of the most abundant atomic elements on Earth. To give you a sense of its abundance, silicon and oxygen are the main ingredients of most beach sand, and a major component of glass, rocks, and soil (which means that you can also find it in actual, not just metaphorical, dirt).
Silicon is a type of material known as a semiconductor. Electricity flows through semiconductors better than it does through insulators (such as rubber and cotton), but not quite as well as it does through conductors (such as metals and water).
But that’s a good thing. In semiconductors, you can control electric current precisely—and without any moving parts. By applying a small voltage to them, you can either cause current to flow or to stop—making the semiconductor (or a small region within it) act like a conductor or insulator, depending on what you want to do.
The first step for making a chip is to start with a thin slice of a semiconductor material, known as a “wafer,” often round in shape. On top of the wafer, manufacturers then create complex miniature electric circuits, commonly called “integrated circuits” (ICs) because they are embedded as one piece on the wafer. A typical IC today contains billions of tiny on-off switches, known as transistors, that enable a chip to perform a wide range of complex tasks, from sending signals to processing information. Increasingly, these circuits also have “photonic” components in which light travels alongside electricity.
Manufacturers typically mass-produce dozens of ICs on a single semiconductor wafer and then dice the wafer to separate the individual pieces. When each of them is packaged as a self-contained device, you have a “chip,” which can then be placed in smartphones, computers, and so many other products.
Though silicon is the most commonly used raw material for chips, other semiconductors are used depending on the application. For example, gallium nitride is resistant to damage from cosmic rays and other radiation in space, so it’s commonly the material of choice for electronic devices in satellites. Gallium arsenide is frequently employed to make LEDs, because silicon typically produces heat instead of light if you try to make an LED with it.
Non-silicon semiconductors are used in the growing field of “power electronics” in vehicles and energy systems such as wind and solar. Silicon carbide can handle larger amounts of electricity and voltage than other materials, so it has been used in chips for electric vehicles to perform functions such as converting DC battery power into the AC power delivered to the motors.
Diamonds are semiconductors too—and they have the greatest ability to conduct heat of any known material. Artificial diamonds are currently used as the semiconductors in chips for aerospace applications, as they can draw heat away from the power loads generated in those chips.
So Why NIST?
Measurement science plays a key role in up to 50 percent of semiconductor manufacturing steps, according to a recent NIST report. Good measurements enable manufacturers to mass-produce high-quality, high-performance chips.
NIST has the measurement science and technical standards expertise that is needed by the U.S. chip industry, and our programs to advance manufacturing and support manufacturing networks across the U.S. mean we can partner with industry to find out what they need and deliver on it.
NIST researchers already work on semiconductor materials for many reasons. For example, researchers have developed new ways to measure semiconductor materials in order to detect defects (such as a stray aluminum atom in silicon) that could cause chips to malfunction. As electronic components get smaller, chips need to be increasingly free of such defects.
“Modern chips may contain over 100 billion complex nanodevices that are less than 50 atoms across—all must work nearly identically for the chip to function,” the NIST report points out.
Flexible and Printable Chips
NIST researchers also measure the properties of new materials that could be useful for future inventions. All of the semiconductor materials I mentioned above are brittle and can’t be bent. But devices with chips—from pacemakers to blood pressure monitors to defibrillators—are increasingly being made with flexible materials so they can be “wearable” and you can attach them comfortably to the contours of your body. NIST researchers have been at the forefront of the work to develop these “flexible” chips.
Researchers are also studying materials that could serve as “printable” chips that would be cheaper and more environmentally friendly. Instead of going through the complicated multistep process of making chips in a factory, we are developing ways to print circuits directly onto materials, such as paper, using technology that’s similar to ink-jet printers.
And while we’ve lost a lot of overall chip manufacturing share, U.S. companies still make many of the machines that carry out the individual steps for fabricating chips, such as those that deposit ultrathin layers of material on top of semiconductors. But what if, instead of these machines being shipped abroad, more domestic manufacturers developed expertise in using them?
To support this effort, NIST researchers are planning to perform measurements with these very machines in their labs. They will study materials that these machines use, and the manufacturing processes associated with them. The information from the NIST work could help more domestic manufacturers develop the know-how for making chips. This work can help create an ecosystem with many domestic chip manufacturers, not just a few, leading to a more resilient supply chain.
“Reliance on only one supplier is problematic, as we saw with the recent shortage in baby formula,” NIST’s Jyoti Malhotra pointed out to me. Malhotra serves on the senior leadership team of the NIST Manufacturing Extension Partnership (MEP). MEP has been connecting NIST labs to the U.S. suppliers and manufacturers who produce materials, components, devices, and equipment enabling U.S. chip manufacturing.
Last but not least, an area of major excitement at NIST is “advanced packaging.” No, we don’t mean the work of those expert gift-wrappers you may find at stores during the holiday season. When we talk about chip packaging, we’re referring to everything that goes around a chip to protect it from damage and connect it to the rest of the device. Advanced packaging takes things to the next level: It uses ingenious techniques during the chipmaking process to connect multiple chips to each other and the rest of the device in as tiny a space as possible.
But it’s more about just making a smartphone that fits in your pocket. Advanced packaging enables our devices to be faster and more energy-efficient because information can be exchanged between chips over shorter distances, and this in turn reduces energy consumption.
One great byproduct of advanced packaging’s innovations can be found on my wrist—namely, the smartwatch I wear for my long-distance runs. My watch uses GPS to measure how far I ran. It also measures my heart rate, and after my workouts, it uploads my running data wirelessly to my phone. Its battery lasts for days; it had plenty of juice left even after I ran a full marathon last month.
Twenty years ago, running watches were big and clunky, with much less functionality. My friends and I had a particular model with a huge face and a bulky slab that fit over the insides of our wrists. When a friend and I opened up his watch to replace his battery, we saw that the GPS receiver was on a completely separate circuit board from the rest of the watch electronics.
Under the small and thin face of my current watch, you will find all its electronics, including a GPS sensor, battery, heart-rate monitor, wireless communications device, and so many other things.
Further development of advanced packaging could produce even more powerful devices for monitoring a patient’s vitals, measuring pollutants in the environment, and increasing situational awareness for soldiers in the field.
Advanced packaging is also a potential niche for domestic manufacturers to grow global market share (currently at 3 percent for this part of the chipmaking process). Chips are becoming so complex that design and manufacturing processes, once separate steps, are now increasingly intertwined—and the U.S. remains a world leader in chip design. NIST’s measurements to support advanced packaging in chips and standards for the packaging process could give domestic manufacturers a decisive edge in this area.
All the NIST experts I’ve spoken to talk about a future in which chip manufacturers work increasingly closely with their customers, such as automakers. The benefit of closer relationships would mean that customers could collaborate with manufacturers to create more customized chips that bring about completely new products.
And as we’ve seen, incorporating chips into existing products tends to make them “smart,” whether it’s an appliance figuring out how long to bake the bread, or solar panels that maximize electricity production by coordinating the power output from individual panels. With more domestic manufacturers on the scene, there are more opportunities to incorporate chips into products—that could also be manufactured in the U.S.A.
I first encountered semiconductor chips in the 1970s, when the U.S. was a dominant force in chip manufacturing. Inside a department store with my mom, I saw pocket calculators on display, and they fascinated me. You could punch their number keys and they would instantly solve any addition or multiplication problem. As a 6-year-old, I thought that they had little brains in them!
Since then, semiconductor chips have been a big part of my life. And after the pandemic, I realize I can’t take them for granted. I’m glad to be part of an agency that is working to create a more resilient supply chain—and bring back chip manufacturing in this country.
About the Author
Ben P. Stein is managing editor in the NIST public affairs office, where he edits and writes news articles and other content about the agency’s research and programs. He has a bachelor of science degree in physics from Binghamton University and a master of arts in journalism from New York University. He has also worked at the American Institute of Physics, where he most recently served as director of its Inside Science news program.
This article was originally published by NIST on October 7, 2022 on its blog, Taking Measure.
Semiconductor Chip Glossary
Semiconductor: Material that can act either as a conductor or an insulator of electricity, depending on small changes in voltage
Silicon: Semiconductor material that serves as the basis for many circuits in industry
Transistor: Simple switch, made with a semiconductor material, that turns on or off depending on changes in voltage and can combine with other transistors to create complex devices
Integrated circuit: Many transistors (anywhere from several to billions) combined to make a small circuit on a chip
Wafer: Thin piece of semiconductor material (such as silicon) that we use as a base for building multiple integrated circuits
Lithography: Process of etching into or building onto the surface of a wafer in order to produce patterns of integrated circuits
Chip: Self-contained piece including the semiconductor surface and integrated circuit, independently packaged for use in electronics such as cellphones or computers
Fab: Industrial facility where raw silicon wafers become fully functioning electronic chips
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