Semiconductors
The semiconductor industry
is a relatively new industry, having come into existence within the last 40
years, and having greatly expanded in the last 20 years. Due to rapid changes
in this industry, manufacturing processes and associated hazardous substances
may be completely altered every few years. This makes hazard assessments more
difficult to complete, and to keep current. Workers in this industry should be
made aware of the known hazards and the possibility of
additional hazards, and use the best available measures to reduce these
hazards.
The past decade has been
increasing globalization of semiconductor manufacturing. Semiconductor
manufacturing uses many chemicals with extremely high respiratory toxicity,
including gases such as arsine and phosphine, strong
acids and bases, dopants and photoactive chemicals.
In semiconductor manufacturing, gases and chemicals are strictly controlled,
but little is known about the occurrence of respiratory symptoms or disease in
this industry. Potential acute respiratory effects of these exposures include
mucous membrane irritation, pulmonary edema and death. Chronic effects may
include airway sensitization and possibly respiratory cancer.
Visit the following site to see a sample semiconductor manufacturing process.
Semiconductor Manufacturing;
An Overview
Arsine is a toxic, colorless gas with a
garlic-like odor at room temperature and atmospheric pressure. Arsine is used
in doping gas mixtures for the preparation of semiconductor materials
containing a controlled amount of significant impurities. Chemically, the
substance is dichloro(2-chlorovinyl)arsine, a liquid whose vapor is highly toxic
when inhaled or when in direct contact with the skin. It blisters the skin and
irritates the lungs. Any part of the body that is contacted by the liquid or
vapor suffers inflammation, burns, and tissue destruction.
Phosphine is a toxic, colorless, flammable
gas. In its purest form, phosphine is almost
odorless, but its commercial grade has a disagreeable, garlic-like odor or that
of decaying fish.
Phosphine is used as an insecticide for the
fumigation of grains, animal feed, and leaf-stored tobacco, and as a rodenticide. Phosphine is also
used as an intermediate in the synthesis of flame
retardants for cotton fabrics, as a doping agent for n-type semiconductors, a
polymerization initiator, and a condensation catalyst.
Acute (short-term)
inhalation exposure to phosphine may cause headaches,
dizziness, fatigue, nausea, vomiting, gastrointestinal distress, pulmonary
irritation, pulmonary edema, and tremors in humans. Chronic (long-term)
occupational exposure of workers to phosphine
may cause inflammation of the nasal cavity and throat, weakness, dizziness,
nausea, and attacks gastrointestinal, cardiorespiratory,
and central nervous systems.