How are chips made?
Chips are printed in layers on a silicon wafer, tested, cut into dies, packaged and tested again.
1. Many chips on one wafer
A chip factory, called a fab, builds many chips at once on a round slice of silicon, the wafer. Like photos on one sheet, it holds dozens of big chips or thousands of small ones.
2. Printed with light
Light shines through a mask, a sheet with a pattern of holes, onto a light-sensitive coating on the wafer. Chemicals then cut away or add material where the light fell, and this repeats for dozens of layers.
3. Test, cut, pack
Each die is tested on the wafer, then the wafer is cut into dies. Only good dies go into packages, and each packaged chip is tested again.
4. No two dies alike
No two dies come out exactly the same. Some run a little faster, and the fast ones often leak more power.
5. 3 nm is a name
Each chipmaking generation gets a name, such as 5 nm or 3 nm (nanometers; a hair is about 80,000 nm wide). Smaller means newer, but it is not the real size of a transistor.
6. Designers and foundries
Many companies design chips but own no fab. A foundry, a company that makes chips for others, builds them.
Words to know
- Fab
- A chip factory (fabrication plant).
- Wafer
- A thin, round slice of pure silicon, often about 30 cm across.
- Die
- One chip cut from the wafer, before packaging.
- Mask
- A sheet that lets light through only where the pattern goes.
- Package
- The case that protects a die and connects it to a board.
- nm (nanometer)
- One billionth of a meter.
- Foundry
- A company that makes chips that other companies design.
- Leak
- Current that slips through switches that are off.
Where you meet it at work
Every die is a little different, so the team tests a feature on many sample chips, not just one.
Check yourself
Why test a feature on many chips, not just one?Think first, then tap to see the answer.
No two dies come out exactly alike.