Presentation on theme: "Chemical Hazard Awareness for MIRC Deborah Wolfe-Lopez Chemical Safety Coordinator."— Presentation transcript:
Chemical Hazard Awareness for MIRC Deborah Wolfe-Lopez Chemical Safety Coordinator
Today’s Topics Acids –Hydrofluoric –Nitric Solvents/ Organics Glycol Ethers Gases –Silane In House Etchants –Piranha –HCl and H 2 O 2
Hydrofluoric Acid (HF) Things That You Should Know Used to etch silicon dioxide Also used to etch glass- Never put HF in Glass Bottles or beakers HF will also etch concrete, releasing a poisonous gas. If an HF spill occurs on concrete, evacuate and call GA Tech Police for help (4-2500)
HF Health Hazard Data: Dermal Exposure Highly corrosive Readily penetrates the skin Causes deep tissue layer destruction Severity and rapidity of onset of signs and symptoms depends on the concentration duration of exposure penetrability of the exposed tissue. Pain may be delayed.
1. CONCENTRATIONS LESS THAN 20% Erythema (redness) and pain may be delayed from 2 to 24 hours, often not reported until tissue damage is extreme. HF
2. CONCENTRATIONS 20 TO 50% - Erythema and pain may be delayed from 1 to 8 hours, and is often not reported until tissue damage is extreme. 3. CONCENTRATIONS GREATER THAN 50% - Produces immediate burning, erythema, and tissue damage.
Mechanism of HF Toxicity Upon penetration into the body, HF disassociates into the hydrogen ion and fluoride ion. The fluoride ion affects tissue integrity and metabolism by: Destruction of tissue, decalcification destruction of bone, production of insoluble salts.
Mechanism of HF Toxicity Loss of calcium, (hypocalcemia), results from precipitation of calcium in the blood as CaF2. Results in loss of calcium from the bones as the body tries to equilibrate the decreased serum calcium.
Mechanism of HF Toxicity Hypocalcemia can be rapidly fatal because calcium is important for muscles, including cardiac muscle, to function properly. The literature indicates that HF exposures of as little as 2% of body area have been fatal
HF -DECONTAMINATION Remove all exposed clothing taking necessary precautions to prevent self exposure. Immediately wash all exposed areas with copious amounts of water (15 minute rule)
HF- “Antidote” CALCIUM GLUCONATE OR CARBONATE GEL – Application of 2.5 to 33% calcium gluconate or carbonate gel or slurry, either placed into a surgical glove into which the affected extremity is then placed, or rubbed into the burn, is recommended. Use calcium gluconate for dermal treatment only
HF- Medical Follow Up All exposures to HF require immediate medical follow up by an occupational health doctor familiar with chemical exposure treatment DO NOT GO TO A “DOC IN THE BOX”
Nitric Acid Inhalation: Corrosive. Effects may include irritation of the nose and throat, labored breathing, as well as lung (pulmonary) edema, damage to the mucous membranes and upper respiratory tract. PULMONARY EDEMA=DELAYED EFFECTS
Nitric Acid Exposure/ Pulmonary Edema Onset can be several hours after exposure, after initial symptoms of acute exposure(coughing, sore throat) have subsided and victim appears fully recovered Characterized by frothy pink sputum Fatal if untreated
Nitric- Medical follow up Exposures to Nitric that are serious enough to cause coughing or burning of the nose and throat require medical follow up by an occupational health doctor familiar with chemical exposure treatment DO NOT GO TO A “DOC IN THE BOX”
Solvents and Organics Such as: Acetone, Methanol (MeOH), Isopropyl alcohol (IPA), Trichloroethylene (TCE) DMSO (resist remover)
What Solvents/Organics Do Typically: –Asphyxiation by displacing O 2, and (some) by affecting the blood’s ability to carry O 2 –Central Nervous system effects, such as narcosis (shut down of the nervous system, your body “forgets” to breathe )
What Solvents/Organics Do Typically: –Target organ effects such as liver, kidney, blood forming tissues damage, demylenation of central or peripheral nerves. –Some solvents are known carcinogens
Symptoms of Solvent/ Organic over exposure: Headache, Dizziness, Nausea, Fatigue…..
If you don’t pay attention and get yourself, or the afflicted person to fresh air
Worth Mentioning… Resist Remover RR2, RR4 –Dimethyl sulfoxide (DMSO) Used as a carrier for experimental drugs Penetrates skin, latex Will “carry” whatever it contacts through intact skin into the bloodstream
Worth Mentioning… Negative Resist –Cyclohexanone, resins, and sensitizers –Cyclohexanone- solvent –“resins and sensitizers”- general terms used to describe what probably are proprietary ingredients: “Resins”, when they come in 2 parts, frequently contain “sensitizers” which are capable of causing an immune response and may eventually cause the person to develop asthema.
Worth Mentioning Trichlorethylene (TCE) –Exposure can be by inhalation or absorption by skin –Along with all the other good stuff, also can cause irregular heartbeat, numbness, liver injury, and cancer
Glycol Ethers Used to strip photoresist / found in a number of photoresists Also found in paints, dyes, nail polish, and cleaning products Classified as E-Series (ethylene glycol ethers) and P-Series (propylene glycol ethers)
E-Series Glycol Ethers Generally considered the more toxic of the two Often found under the trade names Cellosolve and Carbitol Diethylene glycol dimethyl ether and monoethyl ether acetate have both been linked to miscarriages in line workers exposed at below the 5 PPM PEL.
Other E-Series Health Effects Acute- Headaches, dizziness, nausea, fatigue Chronic- Damage to blood-forming tissues of the bone Kidney damage Birth defects Low sperm counts
P-Series Generally considered less toxic but also less researched Include propylene glycol monomethyl ether AKA 1-methyl-2-hydropropane Sold under the trade name Poly-solve and Dowanol
P-Series Health Effects Acute-Headache, dizziness, nausea, fatigue Chronic- liver and kidney damage
Routes of Exposure Respiratory Skin- Readily Absorbed Ingestion- not likely in a clean room
Exposure Avoidance Gloves-Butyl Rubber Ventilation to keep concentrations below the PEL/TLV (5-100 PPM, depending on which GE we are dealing with)
Potassium Cyanide Potential Health Effects Used as a gold etchant In most cases, cyanide poisoning causes a deceptively healthy pink to red skin color However, in sever cases, the skin color may be bluish. Reddening of the eyes and pupil dilation are symptoms of cyanide poisoning.
Potassium Cyanide Corrosive to the respiratory tract. Inhibits cellular respiration May cause headache, weakness, dizziness, labored breathing nausea and vomiting, Which can be followed by weak and irregular heart beat, unconsciousness, convulsions, coma and death.
Potassium Cyanide Skin/Eye Contact Skin- Corrosive. May cause severe pain and skin burns. Solutions are corrosive to the skin and eyes, and may cause deep ulcers which heal slowly. May be absorbed through the skin, with symptoms similar to those noted for inhalation Eye exposure: redness, pain, blurred vision, and eye damage
Silane PYROPHORIC GAS! Silane is a colorless, air-reactive gas, with a choking effect. This gas usually ignites upon contact with air, releasing a dense white cloud of amorphous silicon dioxide The primary health hazard associated with Silane is the potential for severe thermal burns from contact with flames resulting from the spontaneous ignition of this gas
ACUTE POTENTIAL HEALTH EFFECTS: ROUTES OF EXPOSURE –EYE & SKIN CONTACT: Decomposition of Silane will result in the production of amorphous silicon dioxide which is irritating to the eyes and skin
ACUTE POTENTIAL HEALTH EFFECTS: ROUTES OF EXPOSURE –INHALTION: Inhalation of high concentrations of this gas can result in headache, nausea, dizziness, and irritation of the upper respiratory tract. Severe Silane over-exposures via inhalation may result in pulmonary edema and adverse kidney effects.
Other Gases Dichlorosilane –Physical hazards: may ignite with contact to air or water –Health effects: pulmonary edema, frost bite Boron trichloride : hazards similar to Dichlorosilane
Piranha Used to remove organic residues from substrates. Two different solutions are used: Most common – acid piranha: a 3:1 mixture of concentrated sulfuric acid (H 2 SO 4 ) with hydrogen peroxide (H 2 O 2 ) Also used is the base piranha: a 3:1 mixture of ammonium hydroxide (NH 4 OH) with hydrogen peroxide (H 2 O 2 )
Piranha Both are equally dangerous when hot, although the reaction in the acid piranha is self-starting whereas the base piranha must be heated to 60 degrees before the reaction takes off.
Piranha-Physical Hazards There are many things which will cause the reaction to accelerate out of control. "Out of control" can mean anything from the piranha foaming out of its bin and on the deck, to an explosion with a huge shock wave including glove and acid-gown shredding glass sharps. Piranhas burn organic compounds. If you provide sufficient fuel for them (i.e. photoresist, IPA), they will generate enormous quantities of heat and gas.
Piranha- Protective Equipment Full face shield over safety glasses Acid resistant apron over clean room garb Heavy rubber gloves
Piranha-Preparation When preparing the piranha solution, always add the peroxide to the acid. The H2O2 is added immediately before the etching process because it immediately produces an exothermic reaction with gas (pressure) release. If the H2O2 concentration is at 50% or greater, an explosion could occur..
Piranha- Handling Leave the hot piranha solution in an open container until cool. Never store hot piranha solutions. Piranha stored in a closed container will likely explode Used piranha should be left in an open container to cool (several hours) before disposal
Piranha For a complete safety program on piranha see the University of Maryland’s Laboratory for Advanced Material Processing http://www.enma.umd.edu/LAMP/Sop/Pira nha_SOP.htm
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