How_are_microchips_made__-_George_Zaidan_and_Sajan_Saini(360p)

Faysal 🧪 science and technology

Travel into a computer chip to explore how these devices are manufactured and what can be done about their environmental impact.---- Globally, we produce more than a trillion computer chips every year. Which means about 20 trillion transistors are built every second— and this process is done in fewer than 500 fabrication plants. How do we build so many tiny, intricately-connected devices, so incredibly fast?

Transcript

00:00This is a computer chip magnified 500 times. What you're looking at is the top of a computing

00:13city with distinct neighborhoods for different functions. They're linked by up to a hundred

00:18kilometers of ultra-thin copper lines running across 10 or more stacked levels. At the very

00:24bottom, billions of electronic devices generate the digital traffic that pulses across the chip.

00:30The most common of these devices is called a transistor. It's a switch that allows current

00:35to flow if it receives a voltage. Transistors can be as small as 20 nanometers, and more

00:41than 50 billion of them can fit on a single chip. Globally, we produce more than a trillion

00:46computer chips every year. That's about 20 trillion transistors built every second, and

00:53it's done in fewer than 500 fabrication plants, known as fabs. How do we build so many tiny,

00:59intricately connected devices so incredibly fast? The answer involves a technology called

01:06photolithography, which helps us build all the devices on a chip simultaneously. It's

01:11like constructing all the buildings in a city at the same time, and with no tiny construction

01:17crews to help, we build using light as a measuring and sculpting tool. The process starts with

01:23a wafer of silicon, which is doused in solvents and acids to strip it clean before entering

01:28a furnace. Here, oxygen gas reacts with the wafer to form a layer of silicon dioxide. Then,

01:35a liquid called photoresist is spun on and baked to harden. Next, ultraviolet light selectively

01:41illuminates the wafer by passing through or reflecting off a specialized mask. In the lit areas, a reaction

01:48weakens the photoresist's chemical bonds. The wafer is doused in another chemical to wash away

01:53that weakened photoresist, leaving an image of the mask. And an etching machine's reactive gases

02:00remove the exposed oxide, creating windows that drill the mask's pattern down to the wafer's surface.

02:07An implanter then accelerates boron or phosphorus ions and slams them into the patterned openings.

02:14These atoms form electropositive or electronegative regions that change silicon's conductivity,

02:20creating the foundation of the transistor switch. The etched oxide windows, however, create hill and

02:26valley features. Before the next level of copper lines are added, this one's uneven lines must be

02:32polished flat to near atomic precision using a sophisticated grinding process called chemical

02:38mechanical polishing, or CMP. CMP uses a controlled slurry of submicron ceramic particles to gently

02:46scrape and flatten the bumpy features.

02:51These fab tools and many others are used hundreds of times on a wafer to create and link transistors

02:57into computing logic gates and to make connected neighborhoods for memory storage and computation.

03:02FABs run around the clock and it takes about three months to transform a single wafer from pure silicon into hundreds of chips.

03:11With this continuous operation, FABs consume huge amounts of electricity, water, solvents,

03:16acids, bases, process gases, and precious metals.

03:21Wafers are processed in ultra-high purity tool chambers, maintained by pumps running constantly

03:27to sustain a vacuum that resembles deep space. High temperature furnaces never turn off.

03:33FAB air handlers constantly expel filtered air to corral dust and tiny particles away from wafers.

03:39This takes a lot of electricity. The chemicals and purified water used in cleaning create nearly

03:46five gallons of waste per wafer run, which needs to be filtered and pH treated. Meanwhile, CMP slurries

03:53are continually flushed with water to keep their fine particles from forming chunks that would tear

03:57apart the fragile copper lines. This adds five times more liquid waste. FABs plow through vast amounts

04:04of nitrogen and helium gas to run their tools. And other gases used and generated in these tools

04:10are greenhouse contributors. To minimize their emission, machines called scrubbers decompose and

04:16dissolve some gaseous byproducts into treatable wastewater. That uses more electricity and more water.

04:23As computing complexity grows, more copper and precious metals are needed to link up chips.

04:28And new problems arise. Today, PFAS-based photoresists are essential to make ever-smaller

04:34features. But PFAS waste in the environment is ending up in our bodies. And it may be harmful.

04:40Computer chips are modern marvels that have transformed our world. And the factories that

04:44build them are themselves engineering wonders. But as our demand for chips accelerates,

04:49their fabrication is hitting hard sustainability limits. Already, some places are beginning to ration

04:55water to farmers in favor of running FABs. For the sake of the future of computing and our environment,

05:02tomorrow's leaner, cleaner, and greener FABs will need to run even smarter than the very chips they build.

05:10Have you ever wondered what exactly makes your smartphone work? Take a closer look at the

05:15precious minerals that go into our phones with this video and find out how we can make this practice

05:20more sustainable.

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