Page 268 - Materials Chemistry, Second Edition

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4.2. Silicon-Based Applications

Figure 4.17. The evolution of semiconductor clean rooms from 1968 (left) to the present (right). Photos
reproduced with permission from Intel Corporation (http://www.intel.com).

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their clothing with a white “bunny suit” made of Tyvek , a polymeric nonwoven
fabric that exhibits non-lint and antistatic properties, and contains few surface sites
for particulate adhesion (Figure 4.17). En route to the clean room, the worker must
also walk over a sticky pad and pass through an air shower to remove dust particles
from shoes and clothing. The ratings of clean rooms range from Class 1 to Class
10,000 – an indication of the number of particles per cubic foot. As a familiar
reference, in uncontrolled environments such as a typical home or office, the particle
count is 5 million per cubic foot!

4.2.2. Integrated Circuits
An integrated circuit (IC), or chip, represents the brains behind all electronic
devices. An IC is a compilation of billions of complex subunits such as transistors,
resistors, capacitors, and diodes that are all interconnected in a specific manner
depending on the desired application. Incredibly, this minute world of microcir-
cuitry is fitted onto the surface of a thin silicon substrate about the size of a grain of
rice (Figure 4.18)! Though ICs have only been used since the early 1970s, consider
some of the ways our lives have been changed:
Lightweight laptop computers are easily taken with us while traveling;
Cars monitor their emissions and adjust engine conditions for maximum
gasoline efficiency;
Doctors are able to operate on patients from remote locations;
Answers to virtually all questions we may pose are available within minutes
via the Internet;
Televisions may be mounted on walls, with a clarity that rivals viewing
through a window;