ENVIRONMENTAL & HEALTH RISKS OF INTEGRATED CIRCUIT MANUFACTURING

By: Andrew Dyck, Dilan Pauli

What is an Integrated Circuit(IC)? An IC is an electronic circuit that is used

in virtually all electronic equipment. It has helped revolutionize the world of

electronics. The low cost of integrated circuits has

made personal computers, mobile phones, and any other digital machine possible.

What is an IC made of?

An IC is made up of trace elements into the surface of a semiconductor material.

The other materials will then be deposited and used in a pattern to form interconnections between devices.

Silicon monocrystals are the main substrate for IC manufacturing.

What is an IC made of?

Some other materials are used for more specialized applications, such as gallium arsenide.

How are they manufactured? Integrated Circuits are developed in

what are known as fab plants, or semiconductor fabrication plants.

The most important room in fabrication is known as the clean room, where the environment is controlled to eliminate all dust and outside contaminations.

How are they manufactured? The people who work in these clean

rooms must be wearing bunny suits, which completely seal them from the environment around them.

Despite this immaculate clean room, there are health risks and environmental risks as well.

What are the environmental risks? Silicon Valley, where a great portion of

IC fab takes place, have always had environmental risks associated to them.

The chemicals that are used in this process are not very expensive, but the rising costs of chemical disposal contribute to environmental impact.

Environmental Risks

According to the information that we gathered, a typical semiconductor fab plant can use over a million gallons of water every day.

These facilities can also use as much as 240,000 KWh(kilowatt hours) of electricity.

Environmental Risks to Water A facility producing 6 inch wafers can use

around ~2 million gallons of water a day. A facility producing 8 and 12 inch wafers

can use ~5 million gallons of water a day. While some recycling of water does

occur, to get it back in a re-usable state there is extensive chemical treatment required.

Environmental Risks to Water Considering that most IC fab plants are in

such dry places like New Mexico, Arizona, and California, this extensive use of water can drain an already scarce natural resource.

From our sources, we learned that the fabrication off just 1/8th of a wafer can require 3,787 gallons of water as well as 27 pounds of chemicals and 29 cubic feet of hazardous gases.

Past Environmental Issues Contamination of water has always been

an issue in areas surrounding fab plans. A past example of contamination was

that in San Jose in 1981. Fairchild Semiconductor and IBM’s underground storage tanks leaked thousands of gallons of toxic solvents into the ground.

Past Environmental Issues After this incident, drinking water was

found to be contaminated with trichlorethane and Freon, which are toxins commonly used in semiconductor fabrication.

Now there are a number semiconductor-related cleanup sites.

Other Environmental Issues? What is done with these electronic

devices that contain semiconductor devices when they are out of date or broken?

This is a serious issue in IC fabrication. More often than not, these devices are

just put into the trash and wind up in the landfills, posing an environmental risk because of the semiconductor devices left inside of them.

Health Risks in the Industry In the past there have been some

incidents including workers. Some employees who had been

exposed to carcinogenic and toxic materials over the course of time had died from cancer.

The chemicals used in IC fab can cause serious problems.

Health Risks in the industry

Acetone Arsenic Arsine Benzene Cadmium Hydrochloric Acid Lead

Methyl Chloroform

Toluene Trichloroethylene

Some of the environmental contaminates are:

IC manufacturing, concluded The environmental effect of IC

manufacturing can and is a serious issue.

As future Electrical and Computer engineers, it our job to work towards a better solution so that we can improve IC fabrication for future generations.

References

J. Holden,” The Environmental Impact of the Manufacturing of Semiconductors” http://cnx.org/content/m14503/latest/

B. Pimentel, “The Valley’s Toxic History.” San Francisco Chronicle 30 Jan. 2004, final ed.: B1

C. Hayhurst, “Toxic Technology: Electronics and the Silicon Valley.” E: the Environmental Magazine May-Jun. 1997: 4