Microprocessors — The Journey Inside

The article is a part of Intel K12 Education — The Journey Inside

credits — intel

Your computer uses a microprocessor to do its work. Smaller and thinner than a dime, this tiny silicon chip contains millions of transistors that work together to help you do everything from writing a school report to search the Web for the current population of the Svalbard Islands.

But what really is a microprocessor? How are they made? And how do they do all the things they do?

The Robotic Arm

Fetch, Decode, and Execute

  1. Fetch — Microprocessor gets a software instruction from memory telling it what to do with the data.
  2. Decode — Microprocessor determines what the instruction means.
  3. Execute — Microprocessor performs the instruction.

The Best Things Come in Small Packages

See a human hair up close ›

How big is a human hair? About 100 microns in diameter. That means a transistor is just 0.045 microns wide.

What’s a micron? It’s a very small metric measurement. You’re probably familiar with centimeter marks on a ruler. (If not, go look at one.) A micron is .0001 of a centimeter.

A microprocessor transistor then is 0.0000045 centimeters wide. (Want that in inches? It’s 0.00000177 of an inch.)

Journey to the Center of a Microprocessor

Use the different magnification powers of this virtual microscope to see the inner workings of a microprocessor. At the highest magnifications, you see actual circuit paths.

Microscopic Dust

To protect chips from dust during the manufacturing process, they are made in clean rooms. Clean rooms are 10,000 times cleaner than a hospital operating room.

How Do They Make Chips so Small?

Once the areas of the chip have been mapped out by purpose, the circuitry has to be designed down to the individual transistor. With over 500 million of them in modern microprocessors, that’s a lot to keep track of. It’s like building a city by designing every room in every home and building before you even pick up a brick

Recipe for a Microprocessor

Building Skyscrapers on a Wafer

A single microprocessor is like a miniature skyscraper with stairway-like circuits between each floor. Hundreds of these “skyscrapers” can be produced on a silicon wafer at a time.

See a wafer up close ›

From start to finish, a microprocessor takes about 2 months to produce. Fabrication begins with a very thin slice of silicon. Over 300 manufacturing steps later, this silicon wafer holds hundreds of microprocessors. If you could enlarge the wafer to the size of a swimming pool, the surface would look like a miniature city.

Now think small and ask yourself this: How are such tiny circuits put in such a small chip? Good question. No mechanical object or pen could lay down such incredibly microscopic wires. Instead, the pathways for the current are created by using solvents to remove channels of material. These microscopic channels are then etched with chemicals and implanted with electrons to make them conduct electricity.

Explore a Microprocessor

Start with Select. Use your pointer to grab and drag the white circle to the part of the chip you want to view. Use the Focus, Intensity, and Zoom controls to perfect your image.

As you examine the microprocessor, think about how different areas of the chip handle various tasks. Can you tell what this particular area of the chip does — fetch, decode, or execute?

Unless you are a chip designer, it would be hard to guess. Today’s advanced microprocessors with their multiple layers and millions of transistors are too complex. What conclusion can you make? There is incredible processing power for all three tasks in something smaller than your fingernail.

Try Activity 2: Exploring a Microprocessor ›

Note this animation only works in Mozilla Firefox* and Microsoft Internet Explorer*

Exploring Chip Layers

This activity lets you move between the several layers of a chip by focusing on various depths. Use the Focus Depth control to change the layer visible through the microscope.

Try Activity 3: Exploring Chip Layers ›

Note this animation only works in Mozilla Firefox* and Microsoft Internet Explorer*

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