Cleanroom Sizes

A simple guide to understanding the sizes used in the BYU cleanroom

How small is...  

a centimeter?

Definition: Centi means 1 part in 100. Therefore, there are 100 centimeters in a meter.

Notation: cm

Comparison: A centimeter of hair similar to this one, laid out side by side, could contain more than 116 strands.   

a millimeter?

Definition: A millimeter is 1/1,000 of a meter.

Notation: mm

Comparison: If you laid out 1,000 strands of hair similar to the one shown on the right, side to side, the width would be 86 millimeters.   


Definition: Micro is a prefix meaning one-millionth or 10-6 units. There are 1,000,000 micrometers (or microns) in a meter.

Notation: µm

Comparison:A strand of hair can be anywhere from 20 µm (microns) to200 µm in diameter.   


Definition: Nano is a prefix meaning one-billionth, or 10-9,or 1/1,000,000,000!

Notation: nm

Comparison: This strand of hair is approximately 150,000 nm (nanometers) wide. If you were a three nanometers tall, a cross section of this strandcould look like the Grand Canyon.   

an Angstrom?

Definition: An Angstrom is 1x10-10meters, and can be used to measure atomic sizes.

Notation: Å

Comparison: This strand of hair is about 1,500,000 Å in diameter.

When is...

a centimeter used?

The common use of the centimeter is to refer to a wafer size. Our most commonly used wafer is 10.16 cm in diameter   

a millimeter used?

The wrenches used in the cleanroom to maintain the equipment are in the millimeter range.   

a micron used?

Our "large" measurements are usually in microns. Typical hair diameter: 86 microns Common oxide thickness: 1.5 microns   

a nanometer used?

More refined measurements in the cleanroom are on the nano scale.   

an Angstrom used?

This measurement is not commonly used in the cleanroom.

magnified strand of hair
A strand of student hair magnified 10 times. *Width is approximately 86 µm