LSI Logic plant does much to mitigate dangers of chip making
USA Today - Posted at 4:31 p.m. PST Sunday, January 11, 1998
GRESHAM, Ore. -- New semiconductor plants such as the $750
million one being built by LSI Logic here do much to mitigate the
dangers of chip making.
Toxic chemicals travel around the fabrication plant in stainless steel
pipes. The pipes are themselves contained in pipes. That way, a leak
doesn't escape into the workplace. In older plants, chemicals are
sometimes in jugs and transported by hand.
Million-dollar machines with robotic arms apply the chemicals to silicon
wafers, out of which chips are cut. Workers, behind glass panels,
monitor the machines. If all goes right, employees should never come
into direct contact with chemicals.
When the wafers are done at one machine, they are loaded by robot
into an enclosed container and sent via overhead tramway to the next
machine. Wafers can go through 40 to 50 chemical steps before they
are finished.
Exhaust from the machines is piped direct to the plant's exhaust system
so fumes do not escape into the work area.
The exhaust is treated by pollution-control equipment before it is
released. So-called ''scrubbers'' catch the acid exhaust and spray it
with water. The chemical fumes dissolve into the water, which is
treated at the plant before it is released as wastewater. Other
equipment, called thermal oxidizers, cuts emissions of volatile organic
compounds by an estimated 90 percent. They create smog and are
caused by solvents.
The air inside the fab is monitored to provide early detection of gas
leaks. Fresh air is also added. At all times, 30 percent of the air
inside
the LSI plant is fresh, says Dan Peloso, site director.
The LSI plant's toxic acids, gases and solvents are stored in separate
rooms so that they don't accidentally mix and create a chemical
reaction that might result in fumes, a fire or an explosion. Sensors in
the
gas storage room test the air about every 45 seconds to check for
leaks. The sensors are connected to an emergency control room, which
is monitored 24 hours a day.
The acids and solvents are in 55-gallon drums. If one leaks, the
chemical drains through the storage room's perforated floor into a
trench. Once in the trench, emergency response-trained workers pump
it into drums for disposal.
The gases are in pressurized cylinders. They vary in size but are often
5 feet by 9 inches. To protect against leaks, the cylinders are placed
in
cabinets, which are exhausted to pollution-control equipment.
Some of the most toxic gases, like arsine, are in smaller cylinders that
release gas only when attached to vacuum systems. That reduces the
risk of a big release, which is more likely if the gas is in pressurized
cylinders that accidentally open.
Some chemicals used in bigger quantities are stored outside. Sodium
hydroxide, which is used to neutralize the plant's acidic wastewater, is
stored in a 500-gallon tank. The tank sits inside a bigger container so
that spills will be contained.
New plants pollute less than old plants because of improved
pollution-prevention equipment, greener manufacturing processes and,
sometimes, tighter regulations.
In Arizona, plants built before 1988 don't have to have as much
air-pollution equipment as new plants.
Intel's plant in Aloha, Ore., which started production in 1974, is one
of
its oldest plants. It released 20,200 pounds of toxic pollutants in
1995,
the latest Environmental Protection Agency data say. Intel's newer
plant in Rio Rancho emitted 16,000 pounds, yet it is more than twice
Aloha's size.
The LSI plant will separate wastes into 13 waste streams so they can
be more easily recycled. It expects to recycle 30 percent of its water,
60 percent of its cleansing solvents and 40 percent of its acids.
The chip companies aren't purely motivated by health and
environmental concerns in constructing safer and more environmentally
friendly plants. It makes business sense.
Texas Instruments estimates it can save $40 million a year by recycling
solvents used to clean chips. It is running pilot projects in three
plants.
Accidents or chemical spills, which cause evacuations, can cost a
medium-sized plant about $500,000 in lost revenue per day.
''When you have a spill, you have to evacuate. When you have a gas
release, you have to evacuate. Those companies who want to be
profitable cannot afford it,'' says Shaunna Sowell, manager of
environmental health and safety for Texas Instruments.
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