creating computer chips integrated circuits. what is an ic? in the 1950s computers were built with...

Creating Computer Chips

Integrated Circuits

What is an IC?

In the 1950s computers were built with vacuum tubes

A vacuum tube is• A single switch• Produced a lot of heat• Used a lot of power• Burned out frequently

What is an IC?

By the mid 1950s vacuum tubes were replaced by transistors.

A transistor • is a single switch• uses low power• gives off little heat• is reliable

What is an IC?

In 1959 two engineers independently invented ways to put transistorized switches onto a wafer of silicon.

Jack Kilby, working at

Texas Instruments,

Robert Noyce at Fairchild

Semiconductor

What is an IC?

An Integrated Circuit is• hundreds to thousands of

switches (transistors)on a single silicon chip

• low power

• inexpensive

• reliable

More powerful computers are possible with ICs

How are ICs Made?

Design• It takes a team of up to 600 engineers. • The engineers face a task equivalent to trying to

design a small city from the ground up.

How are ICs Made?

Manufacture• Computer chips begin as a material called

silicon.• Silicon is an element like oxygen or carbon

How are ICs Made?

Manufacture• The silicon is crafted into thin, large

"wafer-like" sheets. (wafers)

• The transistors and other components are applied in layers

How are ICs Made?

Manufacture• A single wafer may contain hundreds or

even thousands of individual ICs

• Each IC is removed from the wafer and placed in a package that we know as a computer chip

Creating ICs—Vocabulary

Bunny Suit Mask

Clean Room Micron

Contamination Photoresist

Etching Quality Control

Fab Semiconductor

Fabrication Wafer

Bunny Suit

• Special clothing worn by workers in a clean room that helps to keep human contaminants away from the chips.

Clean Room

• The area of the fabrication plant where the chips are made that is kept extremely clean of dust, dirt and other contamination.

Contamination

• Intrusion or contact with dirt, dust or impurities that adversely affect chip fabrication.

Etching

• The process of immersing the wafer in a chemical bath—usually an acid or solvent—that removes the photoresist that was exposed to light.

Fab

• The fabrication plant that houses the entire business of manufacturing computer chips.

Fabrication

• The process of manufacturing computer chips.

Mask

• A patterned plate or template used to expose selected areas of a wafer to light in the process of fabrication a computer chip.

Micron

A unit of measure that is one millionth of a meter; synonymous with micrometer.

Photoresist

• A light-sensitive material that changes chemically when light shines on to it.

Quality Control

• The stage of testing chips for defects. The smallest mistake, such as a slight misalignment of the mask, can destroy some or all of the chips on a wafer.

Micron

• A unit of measure that is one millionth of a meter; synonymous with micrometer.

Semiconductor

• A substance, like silicon, with electrical conductivity between that of an insulator and a conductor: Most electronic circuits are made with semiconductor components.

Wafer

• A very thin slice of very pure silicon crystal (99.9999% pure)