Transcript Lesson 9: PowerPoint

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?
Jack Kilby,
In 1959 two engineers
independently
invented ways to put
transistorized
switches onto a
wafer of silicon.
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)