FROM SAND TO CIRCUITS

Silicon

Silicon, is the most abundant element on earth except for oxygen, and is used in chip manufacturing because it is a natural semiconductor.

99.9999% pure

To make wafers, silicon is chemically processed so that it becomes 99.9999% pure. The purified silicon is melted and grown into long, cylindrical ingots. The ingots are then sliced into thin wafers that are polished until they have flawless, mirror-smooth surfaces. Then Intel manufactures chips on the polished wafers in facilities called fabs.

2-inch to 12-inch wafers

When Intel first began making chips, the company printed circuits on 2-inch wafers. Now the company uses both 300-millimeter (12-inch) and 200-millimeter (8-inch) wafers, resulting in larger chip yields and decreased costs.

Intel researchers have developed transistors so small that about 200 million of them could fit on the head of a pin. A transistor acts as a switch, controlling the flow of electrical current in a computer chip.

It is estimated that about 10,000,000,000,000,000,000 transistors are shipped each year, or about 100 times the number of ants estimated to be on Earth. The price of a transistor on a chip is now about the price of a single printed newspaper character.

While computer chips look extremely flat, they may actually have over 20 layers of complex circuitry. If you look at a magnified view of a chip, you will see an intricate network of circuit lines and transistors that look like a futuristic, multi-layered highway system.

Why wafers are round?

Wafers start life as long crystals that are "pulled" from a molten bath of silicon. As the crystal is pulled, it forms a long sausage-like shape. The sausage is then sliced into wafers. Although there has been much research in the area of square wafers, no one has been able to produce a defect-free square wafer.

Why chips are square?

Why are partial dies generated over the edge of a wafer when it is obvious that they will be totally unusable? The field is arranged so that as many full die are printed as possible. Old technology exposed the die past the edge of the wafer because a single mask was used for the entire wafer instead of one field being printed at a time and then stepped across the wafer.

Ultra clean air

Intel makes its silicon chips in a special area of the fab, called a cleanroom. Because invisible dust particles can ruin the complex circuitry on a chip, cleanroom air must be ultra clean. Purified air is constantly filtered and re-circulated entering through ceiling to exit through perforated floor tiles so that a cubic foot of air contains less than one particle measuring 0.5 micron (millionth of a meter) across or larger. That's thousands of times cleaner than a hospital operating room.

Bunny suits

Fab technicians wear a special suit in the fab, nicknamed a bunny suit, to keep possible contaminants such as lint and hair off the wafers. The bunny suit became standard Intel cleanroom attire in 1973.

The beloved BunnyPeople™ character frequently appeared in advertising campaigns for the Pentium® microprocessor series beginning in 1997.

Intel fab fun facts

Intel has five 300 mm fabs in production, including three 65 nanometer facilities. Two more 300 mm fabs are under construction with production expected in 2007 and 2008 using Intel's 45 nanometer process.

• Fab technicians typically work three 12-hour shifts one week, and four 12-hour shifts the next.
• Intel's fabs operate 24 hours a day, seven days a week manufacturing silicon chips to supply increasing worldwide demand.
• Intel can build a world-class fab and start high-volume production in less than one year.
• A fab contains about 40 miles of pipe and is built using some 10,000 truckloads of cement.
• Fabs are built using special, pre-cleaned construction materials.
• More than three football fields could fit inside the cleanroom located inside an Intel fab.
• A monorail system used to transport silicon wafers in an Intel fab's cleanroom may have close to three miles of track.

Intel's highest-volume products, the company's highest performing processors, typically are made in the company's most advanced facilities. When the newest, most advanced facilities come online, the next-to-the-newest facilities are then used to make other high-demand products, such as leading-edge chipsets and other performance processors.