A Chip Is Born: Inside a State-of-the-Art Clean Room

By Dylan F. Tweney 

How Chips Are Born: Inside a State-of-the-Art Cleanroom

To build a computer, you must first design and fabricate the tiny processors that rapidly churn through the millions of discrete computational steps behind every one of those digital actions, taking a new step approximately 3 billion times per second.

To do all this, you are probably going to need chip-manufacturing machines from Applied Materials, one of the main suppliers of such equipment to the semiconductor industry.

Applied’s machines subject silicon wafers (such as the Intel wafer shown below) to incredibly intense vacuums, caustic chemical baths, high-energy plasmas, intense ultraviolet light, and more, taking the wafers through the hundreds of discrete manufacturing steps required to turn them into CPUs, memory chips and graphics processors.

The machines themselves are housed within clean rooms whose scrubbed air (and bunny-suited employees) keep the risk of aerial contamination low: A single dust particle from your hair is all it takes to ruin a CPU that might sell for $500. Wired/com recently toured Applied Materials’ Maydan Technology Center, a state-of-the-art clean room in Santa Clara, California, where Applied develops and tests its machines.

Top photo: Jon Snyder/Wired.com
Bottom photo: Intel

Photomask

Photomask

The heart of chip manufacturing is lithography. It’s like silkscreening, except instead of squeegeeing ink through a silk template onto a cotton T-shirt, you’re shining ultraviolet light through a glass photomask onto a silicon substrate coated with an organic compound called photoresist.

Where the UV light shines through, it burns away the photoresist, leaving a pattern on the surface of the silicon. Then the wafer is sent through a chemical bath that etches trenches into the exposed substrate, while leaving the areas covered by the photoresist untouched.

After removing the photoresist, other machines can fill those trenches with various materials, such as copper or aluminum, that comprise the components of the processor.

Photo: Jon Snyder/Wired.com

A mask etching machine and one of Applied Materials' Endura machines

Deposit, Etch, Repeat

As a wafer is sent through the manufacturing facility, it can go through as many as 250 different steps. These processes include depositing films of various materials, then etching them to form transistors and copper wiring.

On the right is one of Applied Materials’ Endura machines. The Endura platform is a modular, configurable system used to deposit metals and metal alloys on the wafer. It has been used in the manufacturing of almost every chip made in the past 20 years, according to Applied.

A mask-etching machine is shown at left. Once a layer has been deposited on the wafer, this machine etches patterns into it.

Photo: Jon Snyder/Wired.com

Lithography Room

The current state of the art for chip manufacturing is 30 nanometers, which means the average size of a chip component is just 30 billionths of a meter across.

Chip manufacturers are currently working on 22-nanometer designs, which are even smaller.

The lithography room is lit with yellow light to avoid interference with the UV light used with the photomasks.

Photo: Jon Snyder/Wired.com

Extreme Vacuum

Extreme Vacuum

A technician works on the touchscreen interface of an Endura system.

On the right is one of the large silver pumps used to create extreme vacuums inside the machine — as low as 10-12 atmospheres.

Photo: Jon Snyder/Wired.com

Centura machine

No Metal Here

The silver metal device on the right side of this Centura machine is a batch loader, used to quickly depressurize a stack of wafers prior to feeding them into the machine for processing.

The green "metal free tool" sign indicates that this machine is used in a part of the process prior to the addition of copper circuits. Copper is a contaminant that can mess up nonmetallic stages of the manufacturing process, so the machines that add copper need to be carefully segregated.

Photo: Jon Snyder/Wired.com

FOUP

FOUP

Over the past several decades, the wafers upon which chips are made have steadily increased in size, enabling manufacturers to cram more chips on each disk. Since 2000, the industry standard has been 300 mm [less than 1/8 inch].

To simplify transportation and minimize the risk of contamination, fabs make use of "front-opening unified pods," or FOUPs. Each one holds 25 wafers in a sterile, clean environment.

Photo: Jon Snyder/Wired.com

Automation and Storage

Automation and Storage

Because a front-opening unified pod full of silicon wafers can be heavy (around 20 pounds), automation is a key aspect of clean-room design.

Every machine in a modern clean room is built around 300-mm wafers. The next generation of chips will be made on 450-mm wafers, enabling even larger economies of scale.

Photo: Jon Snyder/Wired.com

Precision Manufacturing

Precision Manufacturing

Computer chips are only about the size of a fingernail, yet contain hundreds of millions of transistors, not to mention all the wiring needed to connect those transistors into a working machine and connect it to a motherboard and the rest of the world.

They’re made on circular silicon wafers about a foot in diameter, each of which can contain 200 separate but identical processors.

Photo: Jon Snyder/Wired.com

Mail Break

Mail Break

Workers use laptops inside the clean room to take care of other business while the machines are running. They analyze data, write reports and even check Gmail.

Photo: Jon Snyder/Wired.com

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